专题 3 并列句和状语从句框架结构图连词的分类连词常分为并列连词(也叫等立连词)和从属连词两大类。并列句与并列连词的核心考点1.并列句的基本概念并列句是由两个或两个以上并列而又独立的简单句构成的。在并列句中，这些简单句常由并列连词连在一起。并列连词所连接的简单句被称为分句。2.常见的并列连词(1)表示递进或顺承关系：常用的并列连词有 and，not only...but (also)...等。He had plenty of money and he spent it freely.Not only did he speak more correctly，but he (also) spoke more easily.(2)表示选择关系：常用的并列连词有 or，either...or...等。Either you are right，or I am.(3)表示转折关系：常用的并列连词有 but，yet，whereas 等。Jane said she was ill，yet I saw her in the street just now.Some of the studies show positive results，whereas others do not.(4)表示因果关系：常用的并列连词有 so，for 等。It must have rained last night，for it is wet all over.The shops were closed，so I didn’t get any milk.(5)when 也可用作并列连词，意为“那时，这时”，相当于 and at this/that time。常用于下列句式：① sb.was doing sth.when...；② sb.was about to do/going to do/on the point of doing sth.when...；③ sb.had (just) done sth.when...。We were having a meeting when someone broke in.We were about to set off when it suddenly began to rain.(6)while 作为并列连词，意为“而，却”，表示对比。He likes pop music，while I am fond of folk music.1从属连词与状语从句一、时间状语从句1.before 引导的从句中不用否定式谓语。常用如下句型：It will be long before...(得过好久才……)It will not be long before...(过不了多久就……)It was long before...(过了好久才……)It was not long before...(过了不久就……)2.since 后面所用动词不同，该动词所表示动作持续时间的计算方法也不同。It is two years since he joined the army.他参军两年了。It is two years since he smoked.他戒烟两年了。3.as，when，while 用法一览表。类别作用例句asas 表示“当……的时候”，往往和 when/while 通用，但它...
