thatwhichthatwhichw但是c能引导非限制性定语从句,hattthat is useful to the people.

我们应该做一切有益于人民的事情。

Please tell me anything that comes to my mind is Beijing.人们谈论起中国的城市的时候，我首先想到的是北京。

This is the fourth film that has been shown in our school this term.

这是我们校本学期放映的第四部电影。

4. 当先行词为形容词最高级或被形容词最高级修饰时。

例如: The best that I have ever read.

这是我读过的一本最有趣的故事书。

5. 当先行词被 the very, the only, the last, the just, the same等修饰时。

例如: This is the very book that we could do was to wait.

我们唯一能做的事就是等待。

注意：先行词被 that/as you have.我需要有你一样的书。

6. 当先行词既包含人又包含物时。

例如: They are talking of the heroines and their deeds interest them.

他们正在谈论他们感兴趣的女英雄及她们的事迹。

7. 当先行词是疑可代词who,which,what或主句以这些词开头时。

例如: That's a good book that it used to be.

我们的学校现在已不是过去的那个样子了。

9. 先行词为time时，当time表示次数，引导词用that,可省略。当表示时间，可用tat或when引导，都可省略。

例如: I do remember the first time(that) I had ever heard the sweetest voice in the world.

我很清楚地记得当我第一次听到世界上最美的声音的时候。

I did’t remember the exact time when/that)I arrived in Shanghai last month.

我不记得上个月到达上海的确切时间了。

最后，请注意以下几种只能使用which的情况：

1. 在“介词+关系代词”结构中，关系代词必须用

例如: The house in which the teacher is speaking.

这就是老师正在谈及的那本参考书。

注意：如果介词不放在修饰事物的限定性定语从句的句首,that，

例如: This is the question which we’ve had so much discussion.

这就是我们已经多次讨论过的问题

2. 先行词为“those+表事物的复数名词”时，关系代词通常而不是。

例如. You should grasp well which,that可以省略。

如: She likes the child for the very reason which )she loves his father.她喜欢那个孩子因为她爱着孩子的父亲。

He didn't like the way that (=at reason( <span style="font-family:" font-size:10.5pt;"="">that /for which /why ）he came here was to ask for our help.

他来这里的原因是寻求我们的帮助。