19.2 方式状语从句 方式状语从句通常由as, (just) as…so…, as if, as though引导。 1） as, (just) as…so…引导的方式状语从句通常位于主句后，但在(just) as…so…结构中位于句首，这时as从句带有比喻的含义，意思是"正如…"，"就像"，多用于正式…...

18.6 as, which 非限定性定语从句 由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that。As一般放在句首，which在句中。 As we know, smoking is harmful to one's health. The sun heats the earth, which is …...

18.1 关系代词引导的定语从句 关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从...

17.1 引导名词性从句的连接词 引导名词性从句的连接词可分为三类： 连接词：that,whether,if 不充当从句的任何成分） 连接代词：what, whatever, who, whoever, whom, whose, which. 连接副词：when, where, how, why 不可省略的连词：…...

19.9 比较until和till 此两个连词意义相同。肯定形式表示的意思是"做某事直至某时"，动词必须是延续性的。否定形式表达的意思是"直至某时才做某事"。动词为延续性或非延续性都可 以。 正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还…...

19.4 目的状语从句 表示目的状语的从句可以由that, so that, in order that, lest, for fear that, in case等词引导，例如： You must speak louder so that /in order that you can be heard by all. He wrote the name down for fear that(les…...

18.8 what/whatever;that/what; who/whoever 1）what = the thing which；whatever = anything What you want has been sent here. Whatever you want makes no difference to me. 2) who= the person that whoever= anyone who （错）Who b…...

18.3 判断关系代词与关系副词 方法一： 用关系代词，还是关系副词完全取决于从句中的谓语动词。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如： This is the mountain village where I stayed last year. I'll n…...

17.3 名词性wh-从句 1）由wh-词引导的名词从句叫做名词性wh-从句。Wh-词包括who, whom,. whose, whoever, what, whatever, which, whichever等连接代词和where, when, how, why等连接副词。Wh-从句的语法功能除了和that-从句一样外，还可充当介词宾语…...

19.6 条件状语从句 连接词主要有 if, unless, as/so long as, on condition that 等。. if 引导的条件句有真实条件句和非真实条件句两种。非真实条件句已在虚拟语气中阐述。 unless = if not. Let's go out for a walk unless you are too tire…...