1、连词部分连词在句中的作用是把词与词、短语与短语、句子与句子连接起来。它不能在句中单独作句子成分。连词的分类：1并列连词 如：and, or, but, for, 等， 连接并列的词与词，短语与短语，句子与句子。如：Rice and potatoes are common foods. （词与词） Today we can travel by plane. （短语与短语） Many trees lose their leaves in winter, but evergreen trees do not. （ 句子与句子）关联连词是一类成对使用的连词如：bothand, notbut. not
2、onlybut also not onlybut as well eitheror neithernor关联连词必须后接同样的语法结构。如：Either the windows were opened or the door was opened.2从属连词 如：that, whether, when, because, though 等， 用以引导名词性从句和状语从句。从属连词引导的从句不可以被断成一个句子。 如果断开，就错了。 如：When the alarm clock rang. （不完整）though (although)引导让步状语从句，because 引导原因状语从句， 所以th
3、ough(although)不能和并列连词but ，because 不能和并列连词 so一起使用。 只能单独使用。二、复习时需要注意的要点（1）表示选择关系的连词，连接的双方只取其一。常用连词有or, either.or, otherwise例如：1）You can go to Beijing either today or tomorrow 2）You must get up early or you wont catch the early bus.（2）表示转折关系，连接的双方构成对比，意义上有转折。常用连词有but, however, while, only 例如：1） His bro
4、ther is fond of football while he likes basketball.2） You can watch TV, but you must finish your homework first.（3）表示联合关系，联合的双方是对等的，意义上趋向一致。常用连词有：and, both.and, neither.nor, not only.but also, as well as, together with 例如：1） To study English well, we need both diligence and careful.2） That horse is
5、not only the youngest among the five, but also runs the fastest.（4）表示因果关系，连接的双方，互为因果，或者前因后果，或者前果后因。常用的连词有：for, so, therefore 例如：1） It must have rained, for the ground is wet.2） You are in the right, therefore they should support you.实战演练一、例题选讲例1 he did not know much English，he got out his dictionary
6、 and looked up the word.AAsBForCSinceDBecause答案：A提示：for，because和as虽皆可作连词用，表示“因为”，但用法有些区别。for引导的分句总是置于另一分句之后，常常对前一分句加以解释，两个分句之间，总是用逗号分开。because引导的原因状语从句时，往往以why问句，语气比较重，传递的往往是对方未了解的新信息。as引导的原因状语从句时，往往是对方也知道的信息。本句是他拿出词典查，显然，“他知道的英语单词不多”，这是明摆着的事，所以用as最恰当。例2 you dont feel well，youd better stay at homeAB
7、ecauseBSince/IfCForDNow答案：B例3I dont know he has received the package.AifBwhenCwhatDhow many答案：A提示：if表示是否，when不能与现在完成时连用。例4Come tomorrow, I will give it to you.AorBandCthoughDif答案：B提示：and在此处解释为“那么”，表示递进关系。例5The teacher his students likes football.AandBas well asCand alsoDalso答案：B提示：as well as 连接两个主语用靠前原则。例6We were having lunch some one knocked at the door.AasBa soon asCwhenDwhile答案：C提示：when在这里解释“就在那时”
