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 tired.
If you are not too tied,let's go out for a walk.
典型例题
You will be late ___ you leave immediately.
A.unless B.until C.if D.or
答案A.句意：除非你立即走,否则你就回迟到的.可转化为 If you dong leave immediately,you will be late.B、D句意不对,or表转折,句子如为 You leave immediately or you will be late.
比较状语从句
要点：比较状语从句主要运用于形容词和副词的原级,比较级及最高级的句子之中.
原级
1.as…as 和.一样
Jack is as tall as Bob.
捷克和汤姆一样高.
2.not so(as)…as …和不一样
She is not so(as)outgoing as her sister.
她不如她姐姐外向.
比较级
more…than (更)
This book is more instructive than that one.
这本书比那本书由教育意义.
最高级
1.The most…in/of
This book is the most interesting of the three.
这本书是三本中最有趣的.
2.the + 形容词+est…of/in
This road is the busiest street in our city.
这条路是我们城市最繁忙的街道.
知识扩展
lno more than只不过(嫌少的意思)
I have no more than two pens.
我只有两支笔.
It’s no more than a mile to the shops.
去商店不过一英里.
lnot more than不如.；(前者不如后者)
Jack is not more diligent than John.
捷克不如约翰勤奋.
lone of the + 名词(复数)….之一(用于最高级)
Han Mei is one of the best students in our school.
韩梅是我们学校最好的学生之一.