1、当先行词为all, little, much, few, everything, none 等不定代词时关系代词用that而不用which.
There are few books that you can read in this book store.
He asked about the factories and workers that he had visited.
Guilin is one of the most beautiful cities that I have ever visited.
The first sight that was caught at the Great Wall has made a lasting impression on him.
5、当先行词被the only, the very, the same, the right等修饰时,关系代词用that,不用which.
It is the only book that he bought himself.
6、当先行词被all, every, any, much, little, few, no等修饰时,关系代词用that,不用which.
There is no clothes that fit you here.
Which of the books that had pictures was worth reading?
8、在强调句型" It is ... that ..." 中,只用that,不用which.
It is in this room that he was born twenty years ago.
9、在" such (the same) ... as ..." 句型中,关系代词要用as, 而不用which.
We need such materials as (not which) can bear high temperature.
10、表示" 正如... 那样 "," 正象..." 之意时, 用as, 不用which.
Mary was late again, as had been expected.
11、As 引导的定语从句可以放在主句前面, 也可以放在主句后面或主句中间,而由 which引导的定语从句只能放在主句后面。
As we all know, oceans cover more than 70% of the earth.