高中英语作文常用的连接词（推荐10篇）
“They are wasting resources, for example, time, energy and money.”
上面这句话不错，只是转折词“for example”不妥当；应当这样：
“They are wasting resources. For example, they use too much time, energy and money.”
不然就要换一换转折词，改用“such as”或“like”：
“They are wasting resources, such as (or like) time, energy and money.”
不管任何语言，转折词（transitional words）都表演着一个重要角色，就是：承先启后，使句子紧凑，段落相吸，对文章结构，有良性作用。然而有些人几乎不采用转折词的习惯，结果文句蓬松，高下文七零八乱，应该避免。
现在把高中英语作文中的主要转折词，分类列下，供大家参考。
Ⅰ表示“尤有进者”的意思：
Again, also, then, besides, further, furthermore, moreover, next, in addition等，例句：
① Jason teaches diligently. Besides, he writes a lot.
② English is a useful language. For one thing, it is an official language in the UN. Then, it is widely used in business, science and technology.
Ⅱ表示“反见解”：
高中英语作文大全常见连词有But, however, still, yet, after all, for all that, in spite of, on the contrary, on the other hand等，例句：
③ Jim is intelligent but lazy.
④ Singapore is not a big country.On the contrary, it is very small.
Therefore, so, hence, thus, accordingly, consequently, as a result 等，例句：
⑤ Some people are over-ambitious. As a result, they are usually unhappy.
⑥ Tom did not work hard; hence, he failed.
Ⅳ表现“比较关系”：
Likewise, similarly, in a like manner 等，例句：
⑦ You cannot writes without a pen. Likewise, you cannot cook without rice.
⑧ No one is allowed to speak Mandarin in an English class. Similarly, no one is allowed to speak English in a Mandarin class.
Ⅴ表示“举例示范”：
For example, in other words, for instance, that is 等，例句：
⑨ There are some common errors in his composition. For instance, it is wrong to use “he” to replace “the queen”.
Ⅵ表示“结束”：
To sum up, in brief, in short, on the whole, to conclude 等，如：
Our class intended to do a spring outing. Every- one’s opinion differed as for where to spend our spring outing. Some suggested the amusement park while others recommended boating. The rest proposed mountain climbing. After a heated discussion, we reached an agreement: go hiking.
Everyone enjoyed the beautiful scenery along the hillside. However, as we reached the top of the moun- tain, we found wastes and rubbish were thrown every- where. We picked up the litters and collected them in plastic bags. We put the sorted trash into the recy- cling and non-recycling bins.
这篇文章几乎没有用到逻辑连接词,缺乏条理,没有美感可言。
加上逻辑连接词后修改如下:
Our class intended to do a spring outing. At the very beginning, everyone’s opinion differed as for where to spend our spring outing. Some suggested the amusement park while others recommended boating. Still, the rest proposed mountain climbing. Then, after a heated discussion, we finally reached an agreement: go hiking.
At first, everyone enjoyed the beautiful scenery along the hillside. However, as we reached the top of the mountain, we found wastes and rubbish were thrown everywhere. Without any hesitation, we picked up the litters and collected them in plastic bags. Af- terwards, we put the sorted trash into the recycling and non-recycling bins at the foot of the mountain.
此篇文章加上了表示时间和地点的逻辑词,文章内容显得紧凑、有美感,且文章更加完整。由此可知,写作时有意识地使用合适的逻辑词,能大幅度提升作文质量。
那么英语写作时有哪些逻辑词和词组可用呢?
1. 表示句意方向相反的词和词组:
转折关系:but, yet, however, while, on the con- trary, on the other hand, nevertheless, otherwise
让步关系:although, though, despite, in spite of
2. 表示句意方向相同的词和词组:
并列关系:and, as well, both...and, as well as, neither...nor, either...or
递进关系:in addition, besides, moreover, further- more, above all, worse still, not only...but also, what’s more / worse / better, to make things worse
因果关系:because, because of, for, so, as, since, now that, in that, as a result, result in, due to, owing to, thanks to, on account of, therefore, derive / stem / result from
解释关系:for example / instance, that is (to say), in other words, such as, namely
总结关系:in a word, in short, in general, on the whole, to summarize, to conclude, in brief
3. 顺序关系词和词组:
时间顺序:at first, first of all, firstly, secondly, thirdly, to begin with, next, then, later, the next mo- ment, after that, since then, shortly after, at last, in the end, finally, eventually
空间关系:on the right, to the left, on one side of, on the other side, in the middle / center of, at the foot / top / end of
除逻辑连接词和词组外,熟练掌握一些逻辑连接句型也十分有必要,能大幅度提升作文的可阅读性。
以下是英语作文中常见的逻辑连接句型。
1. 开头:
When it comes to..., some think...
There is a public debate today that...
... is a common way of..., but is it a wise one?
Recently the problem has been brought into focus.
2. 提出观点:
Now there is a growing awareness that...
It is time we explore the truth of...
Nowhere in history has the issue been more visi- ble.
3. 进一步提出观点:
... but that is only part of the history.
Another equally important aspect is...
... is but one of the many effects. Another is...
Besides, other reasons are...
4. 提出假想例子:
Suppose that...
Just imagine what would be like if...
It is reasonable to expect...
It is not surprising that...
5. 举普通例子:
For example / instance, ...
... such as A, B and C
A good case in point is...
A particular example for this is...
6. 引用:
One of the greatest early writers said...
“...”, such is the remark of...
“...”. That is how sb. comment / criticize / praise.
“...”. How often we hear such words like this.
7. 讲故事:
..., this story is not rare.
..., such delimma we often meet in daily life.
..., the story still has a realistic significance.
8. 提出原因:
There are many reasons for...
Why...., for one thing, ...
The answer to this problem involves many factors.
Any discussion about this problem would inevita- bly involves...
The first reason can be obviously seen.
Most people would agree that...
Some people may neglect that in fact...
Others suggest that...
Part of the explanation is...
9. 进行对比:
Although A enjoys a distinct advantage...
Indeed, A carries much weight than B when sth. is concerned.
A maybe..., but it suffers from the disadvantage that...
A is to B what / as C is to D.
A and B have sth. in common.
A is similar to B.
The same is true of... / The same can be said of...
The advantages of A are much greater than B.
Compared with B, A has many advantages.
The advantages outweigh the disadvantages.
Wonderful as A is, however, it has its own disad- vantages too.
Although A enjoys considerable advantage over..., it can not compete with B in...
Contrary to widely accepted views, I believe that...
What people fail to consider is that...
It is one thing to insist that..., it is quite anoth- er to show that...
Nothing can rival.
... has drawbacks as well as merits.
A is superior / inferior to B.
... varies from person to person.
A is just the opposite (to B).
A differs from B in that...
... is not the same (as)...
10. 承上启下:
To understand the truth of..., it is also important to see...
A study of... will make this point clear.
11. 让步:
Certainly, B has its own advantages, such as...
I do not deny that A has its own merits.
12. 转折:
But the obvious drawback in their behavior is that...
But the main problem with their argument is that...
But if they adjust their frame of mind a little in the other direction, it is easy to see that...
But in an impartial sense, the public dissatisfac- tion cannot hold every water.
As a result of..., however, things are bound to...
13. 结尾:
From what has been discussed above, we may safely draw the conclusion that...
In summary, it is wiser...
（1）表示增加的过渡词：also，and，and then，too，in addition，furthermore，moreover，again，another，first/ second/ third等。
（2）表示时间顺序的过渡词：now，then，before，after，afterwards，earlier，later，immediately，soon，next，in afew days，gradually，suddenly，finally等。
（3）表示空间顺序的过渡词：near（to），far（from），in front of，behind，beside，beyond，above，below，to the right/ left，around，outside等。（4）表示比较的过渡词：in the same way，just like，just as等。（5）表示对照的过渡词：but，still，yet，however，on the other hand，on the contary，in spite of，even though等。
（6）表示结 果 和 原 因 的 过 渡 词：because，since，so，as a result，therefore，then，thus，otherwise等。
（7）表示目的的过渡词：for this reason，for this purpose，so that等。（8）表示强调的过渡词：in fact，indeed，surely，necessarily，certainly，without any doubt，above all等。
（9）表示解释说明的过渡词：for example，in fact，in this case, actually等。
（10）表示总结的过渡词：finally，at last，in conclusion，in brief，in short，in general，on the whole等。
衔接的句型
在英语的写作中，时常需要用到列举的或者衔接的句型，那么现在就衔接的句型来看有哪些呢？其实根据衔接词本身在文章中起到的作用，主要分为以下四类，即“起”、“承”、“转”、“合”。那么起到衔接的句型到底有哪些呢？下面可以来详细的看一下。
(一)表示“起”的词/词组：用于开篇引出扩展句。
at first 最初 for one thing„(for another)
at present 现在;当今 首先„(其次)„
currently 目前;最后 recently 最近
first(ly)第一 in general 一般说来
in the beginning 起初 one the one hand„(on the other hand)
to begin with 首先;第一 一方面„(另一方面)
first of all 首先;第一 generally speaking 一般地说
in the first place 首先;第一 on the whole 总起来说
lately 最近to start with 首先;第一
presently 现在;此刻 now 现在
(二)有关“承”的常用词语：用来承接上文。
after/after that/afterwards此后 by this time 此时
after a few days 几天以后 certainly 无疑地;当然地
after a while过了一会儿 therefore 因此;结果
also/too 并且;又 for example 例如
at the same time 同时 for instance 例如
beside 此外 for this purpose 为了这个目的
Besides/what,s more 而且;此外 from now on 从此
in addition 此外 second 第二;第二点
in addition to„ 除„之外 secondly 第二
in fact 事实上 similarly 同样地
in other words 换句话说 so 所以
in particular 特别(地)soon 不久
in the same way 同样地 still 仍然
by the way 顺便提一句 then 然后
indeed 的确 third 第三;第三点
meanwhile 与此同时 thirdly 第三
moreover 而且，此外 for another 其次
no doubt 无疑地 such as 正如
obviously 明显地 later 后来
of course当然 truly 事实上;真实地
particularly特别地 unlike „不像„„;和„„不同
what is more 而且;此外
(三)有关“转”的常用词语：用来表示不同或相反的意见。
after all 毕竟 fortunately 幸运地
all the same 依然;照样 however 然而;无论如何
anyway 无论如何 in spite of 尽管„„;虽然„„
at the same time同时;然而 luckily 幸运地 but 但是 by this time 此时
though/although 尽管 no doubt 无疑地
in/by contrast 对比之下 on the contrary 相反地 even though即使 otherwise 否则 still 仍然 unfortunately 不幸地
in fact 事实上 unlike 不像„„;和„„不同 as a matter of fact 事实上 yet仍;然而;但是 especially 特别地
(四)有关“合”的常用词语：用于小结上文或结束本段落的内容。above all 最重要的是 accordingly 于是 as a result结果 in sum 总之，简而言之
as has been noted 如前所述 in summary 简要地说
as I have said 如我所述 on the whole 总体来说;整个看来 at last 最后 therefore 因此 by and large 一般说来 thus 因此
briefly 简单扼要地 to speak frankly 坦白地说 by doing so 如此 to sum up 总而言之 eventually 最后 surely 无疑
finally 最后 to conclude 总而言之 in brief 简言之 no doubt 毫无疑问
in conclusion 总之，最后 undoubtedly 无疑 in short 简而言之 truly 的确 in a word 总之 so 所以
certainly 当然地;无疑地 obviously 显然 all in all 总之
初中英语作文常用连接词和亮点句子
1.表文章结构顺序：First of all, Firstly/First, Secondly/Second„next „And then, Finally/In the end/ At last
2.表并列补充关系的(递进关系)：What’s more（甚至）/ What’s worse（更糟糕的是）, even（甚至），Especially（特别是）
Besides（除此之外）, Moreover（甚至）, Furthermore, In addition（除此之外还有）,not only „but also 不但„而且，at the same time 同时
3.表转折对比关系的：However, On the contrary, but, Although+clause（从句）,（不与but连用）
Despite/In spite of+n/doing 尽管„但是„
4.用来陈述正反方的不同观点（一般用于议论文章中）：On the one hand„ On the other hand„一方面，又一方面
；Some„, while others„一些人认为„而另一些人认为„
Everything has two sides„(食物都具有两面性)some people hold the view that „while the others prefer the view that „（一些人坚持这种观点，而另一些人更喜欢另一种观点）
5.表因果关系的：Because（不与so连用）, As（由于，因为），So, Therefore（因此）, As a result(结果)，thanks to（多亏)because of/as a result of（由于）, without, with the help of...（在„的帮助下），6.表进行举例说明：For example+句子（意思是：例如）可以用于句中，句首，句尾； such as„and so on 7.表陈述事实：In fact 事实上
8.表达自己观点：As far as I know / as far as I am concerned In my opinion /for my apart，to tell the truth 说实话
；to be honest 诚实地说，generally speaking 通常来说
这些短语一般都用于最后一段的开头，用来陈述自己的观点。
9.表总结：In short（总之）、In a word（总之）.一般也用于最后一段表示总结。
10.as is known to（us）all，as we know.（据我所知），It is said /reported that + 句子 据说/报道„ recently 最近
用于作文开头，其后一般用现在完成时态 with the development of the（economy）随着（经济）的发展等连接词或者短语（一般用于句首，用于陈述事实）
11.„„已成为人的关注的热门话题，特别是在年青人当中，将引发激烈的辩论。
例如：„„has become a hot topic among people，especially among the young and heated debates are right on their way.12．连接各类从句的连接词：
时间状语从句：when, not„until, as soon as 目的状语从句：so that+clause;to do（为了）
结果状语从句：so„that+clause, too„to do（太„„以至于„„）条件状语从句：if, unless（除非）, as long as（只要）
让步状语从句：though（尽管，不与but连用）, although（尽管，不与but连用）, even though(即使), even if（即使）
no matter what/when/where/who/which/how（无论„）比较：as„as„, not so„as„, than 13.用来提建议的句型：
I suggest / advice that you should do 我建议你做„
If I were you, I would do„(虚拟句型)我要是你的话，我会做„
It’s best to do 最好做„
You had better(not)do 最好(不)做
how about / what about doing „怎么样?
I think you should do 我认为你应该„
Why not do / why don’t you do„? 为什么不„
Only in this way can we do it well(这句话一般用于所提出的建议
之后，意思为：只有通过这种办法,我们才能把它做好.注意: 该句型用倒装语序，用得好的话肯定会成为该篇作文的亮点)
above all, accordingly, all in all, altogether, as a result, by and large, briefly speaking, consequently ,finally, generally speaking, hence, in a word, in brief, in conclusion, in general, in short, in summary, on the whole, so, therefore, thus, to be brief, to conclude, to summarize, to sum up
1)表层次:
first, firstly, to begin with, further, in the first place
second, secondly, to start with, still, furthermore
third, thirdly, what is more, last, last but not least
Also, and, then, next, besides
and equally important, too, moreover
Besides, in addition, finally
2)表转折：
by contrast although though yet
at the same time but despite the fact that even so
in contrast nevertheless even though for all that
notwithstanding on the contrary however in spite of
on the other hand otherwise instead still
regardless
3)表因果：
therefore consequently because of for the reason
thus hence due to owing to
so accordingly thanks to on this account
since as on that account in this way
for as a result as a consequence
4）表让步：
still nevertheless concession granted naturally
in spite of all the same of course despite
even so after all
5)表递近：
furthermore moreover likewise what is more
besides also not only...but also...too in addition
6)表举例：
for example for instance for one thing that is
to illustrate as an illustration a case in point
7)表解释：
as a matter of fact frankly speaking in this case namely
in other words
8)表总结：
in summary in a word thus as has been said
in brief in conclusion altogether in other words
to conclude in fact finally in simple terms
indeed in short in particular that is
in other words of course on the whole to put it differently
namely in all therefore to summarize
在雅思写作的四大评分标准当中，连贯性与衔接性是其中的一项评分标准，连贯性与衔接性其中一方面就是用连接手段（即连接词）来实现的。连接词本身是非常繁琐的知识，在教授连接词时也会遇到很多困难，那么学连接词首先把连接词词性掌握并掌握各词性的用法，学连接词就简便得多。朗阁海外考试研究中心分析认为，连接词大体可分为四种词性：连词，副词，介词和短语，它们各自的用法又不一样。
连词
如but, and,后接句子，连接并列句时前面逗号可有可无。当然连词也可放句首，这一点在考官范文里有很多体现。
例：In the past, populations were partly regulated by frequent war and widespread disease, but in recent years the effects of those factors have been diminished.(并列句中的连词)
段落开始： But how should it be achieved(连词放句首)
介词
如before, despite：后接名词或动名词
例：Before talking about the essential role of death penalty, you have to think about the meaning, and the purpose, of any kind of punishment.副词
副词连接并列句，前面用句号或分号，后面用逗号（当然，如果副词前用句号，那就是另起一句了，不称之为并列句）
例：In many places today, children start primary school at around the age of six or seven.However, because it is more likely now that both parents work, there is little opportunities for children to stay in their own home up to that age.(副词另起一句)
The crime rate is increasingly high;therefore, the government needs to enforce more laws to curb this situation.(副词在并列句中)
短语
如on the contrary, in addition：用法和副词用法完全一样
例：They feel this is one area of life where they have the right to make decisions for themselves.For that reason, it would seem that the best approach would be work by persuasion rather than compulsion.The government plays a crucial role in scientific research;on the other hand, private companies hold certain advantages in conducting scientific research.(短语在并列句中)
掌握连接词的四大词性及用法以后，连接词的教学和运用就容易展开。我们可以参看考官范文，看看各类关系的时候考官如何使用连接词，使文章凸显出来。
因果关系
根据词性及用法可归结于:
because / since/ as / for, so(连词)，because of/ due to / owing to/ as a result of(介词)
for that reason/as a result/ therefore/ accordingly(短语和副词)
例：I think the amount of waste produced is also as a result of our tendency to use sth once and throw it away.（可代替词汇because of/ due to / owing to）
转折关系
根据词性及用法可归结于
but/ while/ yet/ whereas(连词)
however/ nonetheless/ nevertheless/ on the other hand（副词和短语）
rather/ instead（副词）
rather than/ instead of（介词）
例：Because it is more likely now that both parents work, there is little opportunity for children to stay in their own home to 6 or 7.Instead, they will probably go to a nursery school when they are much younger.（可代替词汇 rather）
My own view is that there is no one major influence in a person’s life.Instead, the traits we inherit from our parents and the situations and experiences that we encounter in life are constantly interacting.(考官钟爱词汇)
递进关系
moreover/ what’s more/ furthermore/ besides/ in addition(副词)
in addition to/ besides/ apart from（介词）
例: Apart from these tensions caused by cultural differences, international tourism may also lead to conflicts between tourists and a local community.(可代替词汇：in addition to, besides)
让步关系
although/ though/ even though/ even if/while(连词)
in spite of/ despite（介词）
no matter how/when/ what（连词）
例： In spite of this, the obvious benefits of computer skills for young children cannot be denied.They are allowed to buy whatever they want, no matter how much it cost(考官高分句式)
学生学习和教师授课时，可根据以上方法对不同的关系词（如表结果，目的的连接词）进行归类。
翻看考官范文，我们发现当中有些副词（最典型为 for example, however, therefore）放在句子中间，前后用逗号隔开，这种句式也是相当的经典。例如：
在中学阶段, 转折连接词在英语写作中起着不可或缺的作用,大量的研究表明,中学生在使用转折连接词时往往出现多用、少用、甚至误用的现象。然而,转折连接词作为语篇衔接的手段之一,许多学者和教师将转折连接词作为衡量写作质量的一个因素, 但是关于衔接手段与写作质量方面的各种研究结果经常矛盾。Halliday & Hasan在1976年出版的《英语的衔 接》一书 ,标志着衔 接理论系 统研究的 开始。基于此,国内许多学者运用语料库及其他方法对中国不同水平学习者在各种体裁写作中衔接手段运用的情况进行过研究, 但少数民族地区的相关研究甚少。因此,很有必要就转折连接词在少数民族地区中学生英语写作中的运用情况进行研究, 以透视写作中存在的主要问题,并提出相应的解决办法,以期对中学英语写作教学有所启示。
二、 研究设计
1.数据收集 。本研究 收集了甘南 某中学300份期末试卷,其中99份空白,余下201份共16286词次自建语料库,称为self-made corpus,对其写作 部分进行查找、标注与分析,将桂诗春、杨惠中建立的中国学习者英语语料库作为参照语料库。
2. 转折连接词 的选择。 本研究根据Halliday &Hasan的分类方法 , 把以下转折连接 词作为研 究对象:but,yet,however,whereas,instead,still,on the other hand,on the contrary,by contrast等。
三、 结果与讨论
1. 不同语料库转折连 接词的使 用。统计 结果显示,在自建语料库与CLEC语料库中,中学生使用连接词的频率尚可,都存在一定的错误使用和重复使用情况,但民族地区的中学生相对出现的错误使用与重复使用偏多,差不多高出两倍,这说明民族地区中学生的英语写作水平较差,基础知识相对薄弱。
2.具体转折连接 词的使用情 况。统计 结果显示 ,中学生对转折连接词使用频率存在很多共同点,都是but最多,however次之,on the other hand最少但他们之间对连接词的使用情况存在着较大差异民族地区中学生过多使用个别转折连接词, 如buthowever,yet等。多用but,可能是因 为受口语 影响再加他们学习基础薄弱,缺乏必要的语体意识。过多使用yet,则表明受汉语的影响,忽略了yet位置的灵活性及正确用法。出现这些差别可能是因为受民族地区文化差异、生活环境及英语教学特点的影响。民族地区的教师迫于应试压力, 在写作教学中过分强调语篇的连贯性, 为学生总结出很多连接词让学生死记硬背,可学生却没真正掌握其用法及细微差异。大多数学生虽然能背出很多连接词, 但在真正使用时却不知道其准确用法。
四、 对民族地区英语教学的启示
英语写作作为英语语言学习的基本技能之一,最能体现出学生的英语综合素质。通过这次对甘南藏族自治州中学生英语写作中转折连接词使用情况的探讨, 笔者认为民族地区英语教学应注意以下几点:
1.课堂输入过程 中培养学生的 语体意识。课堂输入对语言学习是非常重要的,连接词相对较简单,但要准确运用却不容易。所以在课堂教学中,教师应尽量帮学生分辨其差异, 正确区分口语词汇和书面语词汇,一方面应准确解释每个连接词的用法,另一方面应把连接词在语境中的实际使用展示给学生,有意识训练学生使用不同语体写作以培养他们的语体敏感度。
2. 注重英汉 差异对英 语写作的影响。 英汉两种语言在表达方式上往往存在着很大的差异, 尤其是语篇的表意及衔接方式。在教学中,可运用语料库培养学生的语感, 对照自己的语言输出找出连接词使用上的差距,提高其使用语言的地道性。
3. 注重输入 的同时还要注 重输出。 输入的最终目的是输出。 无论是口头形式的输出还是书面形式的输出,都可以引起学习者对自身语言问题的注意,帮助学生了解到自身的中介语与目标语之间的差异, 修正自己的输出, 在未来的学习中找寻解决问题、减少差异的办法,提高英语写作水平,最后能自如地运用目标语。
雅思写作常用逻辑连接词 在雅思写作中，不同逻辑关系的表达就意味着要使用不同的句式结构，不同的连接词。因此，连接词在写作中是否能正确的使用就决定着文章逻辑关系是否合理。笔者在多年的教学中发现，有的考生不明白在写作中该使用怎样的连接词，有的考生不知道连接词的使用是否正确。本文中，朗阁雅思培训中心的专家将总结一些写作中常用的连接词。
一、常见列举用转折词语
1.for one thing, for another, above all things;
2.to begin/start with, next/besides/moreover, last/finally;
3.in the first place, in the second, in the third,(and)best of/worst of all;
4.one of these, another,(there is)still another(reason/factor);
上述词组的意思是：
1.首先；其次；最重要的是；
2.首先；然后/此外/而且；最后；
3.第一，首先；第二；第三；最好的是/最糟糕的是；
4.其中一个；另一个；还有一个（原因/因素）；
二、常见对比转折词语
1.but, but on the contrary, but on the other hand, but then;
2.by contrast, in contrast, in contrast with/to, as a contrast to, as opposed to;
3.by contraries, on the contrary, to the contrary, contrary to(A), opposite to, in opposition to;
4.whereas, while, while on the other hand, while on the whole, yet, however;
5.(as)compared with/to, by comparison, in comparison with, by comparison to
6.First..., Next..., Last...;
7.In the first / early / initial / infant period / stage / phase（或In its infancy）..., In the second / middle / adult / ripe period / stage / phase..., In the third / last / closing / later / concluding period...;
8.One step(way/course/approach/secret/trick)..., Another step..., Still another step...;
9.The first measure/step/move..., Next to it comes..., And the last/final/the most important measure...;
10.The direct experience/lesson/factor/way（或One lesson）...The indirect experience/lesson/factor/way（或The other lesson）...上述词组的意思是：
1.但是；但相反地；但另一方面；但是接下去；
2.通过对比；经过对比；经与…对比；作为与…的对比；作为…的对照；
3.相反；相反；相反；与A相反；与…相反；与…相反；
4.然而；然而；然而另一方面；然而整体而言；然而；然而；
5.跟…相比
6.首先…；其次…；最后…；
7.在第一个/早期/开始/婴儿时期/阶段；在第二个/中间/成人/成熟时期/阶段；在第三个/最后/结束/后面的阶段；
8.一个措施/方法/做法/秘密/计策是…；另一个措施是…；还有一个措施是…；
9.第一个措施是…；接着是…；最后一个/最重要的措施是…；
10.直接经验/教训/因素/途径是（一个教训是）…；间接经验/教训/因素/途径是（另一个教训是）…
三、常见对比转折句型
1.But the obvious(fatal/serious)flaw(defect/drawback)in their argument
(attitude/idea/view/action/behavior)is that.../But the basic(main/great/key/ big)problem with their argument(...)is that...e.g....that they are ignorant of(blind to)a bare fact: Social changes have attached new meanings and values to the division between good and bad.2.But if...it is(not)easy(difficult/hard)to see(find/discover)that...e.g.But if they adjust their frame of mind a little in the other direction , it is not hard for them to find that life is just as promising as before.3.Too much emphasis(attention/stress/concern/significance)placed on(given to/focused on/attached to/paid to)the negative(sunny/gloomy/bright)side of the issue, however, may...（如mislead/confuse/cloud/bias/disturb our judgment of it.）A
e.g...., however, may mislead us to form a pessimistic estimate of current
situations.或..., however, may stop us from rendering(passing/forming/having)a fair(correct/clear/infallible/wise)judgment on it.4.But in most cases/from the point of view of justice(objectivity)/as a matter of fact/in a very true sense, their(public/general)satisfaction
(dissatisfaction/disillusionment/concern)with...（或their criticism of.../their argument for/against.../their objection to.../their approval for...）can not.../is..., for...e.g.But in an impartial sense, the public dissatisfaction can not hold every water, for our society is still abundant in goodness and beauty.5.As a result of..., however, things would/are bound to...e.g.As a result of such an utter indifference to vicious behavior, however , things would be past saving/mending/all the hope.上述句型的意思是：
1.但他们辩论/态度/观点/看法/行为中的明显/致命的/严重的缺点/缺陷是…；他们辩论的基本/最大/主要问题在于…
例：…他们忽视了一个赤裸裸的事实：社会变革给善恶的区分赋予了新的意义和价值。
2.但如果…很（不）容易/难发现…
例：但如果他们稍微调整一下思路，就不难发现生活还是跟以前一样前途光明。
3.然而，对问题负面/正面/阴暗面给予/集中/附加了太多的强调/注意/关注会…（如误导/混淆/掩盖/歪曲/干扰我们对它的判断）
例：然而，…会误导我们对目前的形势形成悲观的估计。或：然而，…会阻碍我们对其形成/有一个正确的/清楚的/无误的/明智的判断。
4.但大多数情况下/从公正（客观）的角度来看/实际上/真正意义上，他们/公众/对…的满意/不满/幻灭/关注（或：他们对…的批评/他们对…辩解（辩驳）/他们对…的反对/他们对…的支持）不能…/是…，因为…
例：但从公正的角度来看，公众的不满并不都有道理，因为我们的社会仍然充满着善与美。
5.然而，作为…的结果，事情会注定…
例：然而，作为对不良行为全然漠视的结果，事情将成为过去，希望还在。
四、常见情景/参照物设定的词语或结构
1.when, if, the other day in a certain place, suppose/imagine/assume(that...), in(the)course/time of...for instance, in the event of等；
2.in the case of, as for/to, as far as...is/are concerned, The same is true of..., when compared with, in comparison with, by comparison等；
3.If there is anything that comes close to/is comparable to/with...,...there is hardly, a thing that compares favorable with/can rival...上述句型的意思是：
1.当…的时候；如果；几天前在某地；假设/想象/倘使…；在…期间；例如；万一…；
2.关于；关于；关于；关于…也是一样；当与…相比；当与…相比；通过比较；
时间状语从句：when, not…until, as soon as
目的状语从句：so that+clause; to do(为了)
结果状语从句：so…that+clause, too…to do(太……以至于……) 条件状语从句：if, unless(除非), as long as(只要)
让步状语从句：though(尽管，不与but连用), although(尽管，不与but连用), even though(即使), even if(即使) no matter what/when/where/who/which/how (无论…) 比较：as…as…, not so…as…, than
13.用来提建议的句型
I suggest / advice that you should do 我建议你做…
If I were you, I would do… (虚拟句型)我要是你的话，我会做… It’s best to do 最好做…
You had better (not) do 最好(不)做 How about / what about doing …怎么样? I think you should do 我认为你应该…
Why not do / why don’t you do…? 为什么不…
Only in this way can we do it well (这句话一般用于所提出的建议
之后，意思为：只有通过这种办法,我们才能把它做好. 注意: 该句型用倒装语序，用得好的话肯定会成为该篇作文的亮点)
关键词：二元关系,性质,蕴含连接词,关系图
离散数学是数学学科的一个分支,主要以离散结构和离散数量为研究对象,是计算机专业的重要基础课程。通过对离散数学的学习,不仅有助于培养和锻炼学生的逻辑及抽象思维能力,更是为学习计算机专业课程打下坚实的基础。
在离散数学中,二元关系是非常重要的内容,对其性质的理解至关重要。二元关系的性质主要包括五个方面:自反性、反自反性、对称性、反对称性及传递性,对二元关系性质的判定是离散数学教学中的难点。本文从二元关系性质的概念入手,通过蕴含连接词对各种性质加以分析,得出了判定二元关系性质的有效方法。
1 二元关系性质的定义
二元关系有五个方面的性质,分别描述了一个对象、二个对象和三个对象之间可能存在的不同关系。设R是定义在集合A上的二元关系:
1)自反性:若对每个x∈A都有xRx,则称R是自反的。
2)反自反性:若对每个x∈A都有x Rx,则称R是反自反的。
3)对称性:对任意x,y∈A,若xRy,则yRx,就称R是对称的。
4)反对称性:对任意x,y∈A,若xRy且yRx,则x=y,就称R是反对称的。
或者:对任意x,y∈A,若
5)传递性:对任意x,y,z∈A,若xRy且yRz,则x Rz,就称R是传递的。
2 蕴含连接词及对关系性质的定义
2.1 蕴含连接词的定义
设p,q是命题,复合命题“如果p,则q”称为p蕴涵q。称p为条件,q为结论。规定p→q为假当且仅当p为真而q为假。
其真值表如表1。
2.2 蕴含连接词对关系性质的定义
1)自反性:∀x∈A→
2)反自反性:∀x∈A→
3)对称性:∀x,y∈A∧
4)反对称性:∀x,y∈A∧
5)传递性:∀x,y,z∈A∧
通过上表可以判定:
如果集合A上三个对象之间,不存在有序对,关系图上没有有向边,则满足传递性;
如果集合A上三个对象之间,只存在一个有序对,关系图上只有一个有向边,则满足传递性;
如果集合A上三个对象之间,存在
如果集合A上三个对象之间,存在两个有序对,只要不存在第一顶点到第二顶点和第二顶点到第三顶点的方向一致的有向边,则满足传递性;
如果集合A上三个对象之间,存在第一顶点到第二顶点和第二顶点到第三顶点方向一致的有向边,但是不存在第一顶点到第三顶点的方向一致的有向边,则不满足传递性。
总合起来,传递性只有
几种二元关系的性质,都反映在蕴含表达式的求值上,蕴含表达式的值为真,该性质就成立,为假则该性质就不成立。
3 通过蕴含连接词对关系性质的理解与应用
例1,判断下图中各二元关系的性质,并说明理由。
解:
1)该关系是对称的,因为无单向边。它不是自反的也不是反自反的。因为有的顶点有环,有的顶点无环。它不是反对称的,因为图中有双向边。它也不是传递的,因为图中有边<3,1>和<1,3>,但没有从3到3的边,即通过3的环。
2)该关系是反自反的但不是自反的,因为每个顶点都没有环。它是反对称的但不是对称的,因为图中只有单向边。它也是传递的,因为不存在顶点x,y,z,使得x到y有边,y到z有边,但x到z没有边,其中x,y,z∈{1,2,3}。
3)该关系是自反的但不是反自反的,因为每个顶点都有环。它是反对称的但不是对称的,因为图中只有单向边。但他不是传递的,因为2到1有边,1到3有边,但2到3没有边。
例2,设A={1,2,3,4,5},R={<1,1>,<1,2>,<3,2>,<1,4>,<5,4>,<5,1>},判断二元关系R的性质。
解:画出该关系的关系图R如下:
1)考察自反性和反自反性:由于图中只有一个顶点上有环,2、3、4、5上面都没有环,因此该关系不满足自反性,也不满足反自反性;
2)考察对称性和反对称性:考察由于该关系中,不同元素之间最多只有单向的有序对,图中不同顶点之间最多只有一条单向边,因此该关系不满足对称性,但是满足反对称性;
3)考察传递性:
对于A中元素1,<1,1>∈R∧<1,2>∈R→<1,2>∈R,满足传递性的条件,属于表2中编号(8)的情况;<1,1>∈R∧<1,4>∈R→<14>∈R,满足传递性的条件,属于表2中编号(8)的情况;
对于A中元素2,4,由于不存在2开始的有序对,,满足传递性的条件,属于表2中编号(1)的情况;
对于A中元素3,<3,2>∈R,满足传递性的条件,属于表2中编号(2)(3)(5)的情况;
对于A中元素5,<5,1>∈R∧<1,2>∈R→<5,2>∉R,不满足传递性条件,属于表2中编号(7)的情况;
根据定义,并不是所有元素都满足传递性的条件,因此不满足传递性。
结论:该关系不是自反的,也不是反自反的,不是对称的,是反对称的,不是传递的。
4 总结
在离散数学的二元关系中,关于二元关系性质的判定既是重点,也是一个难点。,通过蕴含连接词在二元关系定义中的作用,对关系性质加以判定,能较好地对抽象概念和性质加以具体化分析和描述,解决在理解和应用中的模糊概念和误区,为后期学习关系的闭包与合成打下良好的基础。
参考文献
[1]耿素云,屈婉玲,王捍贫.离散数学教程[M].北京:北京大学出版社,2002.
[2]耿素云,屈婉玲,张立昂.离散数学[M].北京:高等教育出版社,2008.
[3]匡能晖.二元关系的性质的进一步研究[J].延边大学学报(自然科学版),2009(3).
[4]郭键,赵明茹.判定二元关系传递性的几种方法[J].大庆师范学院学报,2008(5).
[5]陈光喜,古天龙“.离散数学”精品课程教学改革实践[J].桂林电子科技大学学报,2007(4).
1、按照事情发展的先后或时间顺序
（1）First, then/ next, after that, finally（2）soon, suddenly, as soon as, from now on(从现在起)，at the same time, not…until…,when, while
2、表示举例
for example,…
such as(不能位于句首！)+n/ V-ing
3、表示递进
besides（另外），what’s more(更重要的是)，what’s worse(更糟糕的是)Luckily/ Unluckily….4、表示转折
However, but, though, instead of
5、表示原因
thanks to+ n, because of +n, because
6、表示结果
as a result(结果), so…that…, such…that…；Therefore(因此)
7、表示目的
so that+句子，in order that+句子，in order to do sth.8、表示并列
not only…but also…, both…and…, either…or…
neither…nor…;on the one hand,…,on the other hand,…(一方面…,另一方面…)
9、表示对比
While(而)，prefer(doing)A to(doing)B(比起B，更喜欢A), would rather do … than do…(宁愿…而不愿…)
10、表示利弊
be good/ bad for…;have a great influence on sb； be harmful to +n
11、表示喜欢
love /like / enjoy…;be interested in …;be good at…
12、表示总结
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