1、在英语限制性定语从句中,必须要用关系代词that的情况如下：
用法一：(1)当先行词是不定代词all,much, little, something, every-
thing, anything, nothing,none等时,例子介绍如下：
Do you have anything that you want to say for yourself?
你有什么要为自己说的吗?
You should hand in all that you have
你应该上交你所有的东西。
2、用法二：(2)当先行词被 the only, the very,any,few, little,no,all等词修饰时,例子介绍如下:
This is the very person that i'm waiting for.
这正是我正在等的那个人。
The only thing that we can do is to give you some money.
我们唯一能做的就是给你一些钱。
用法三：(3)当先行词是形容词最高级或者是先行词的前面有形容词最高级修饰时,例子介绍如下:
This is the best way that has been used against pollution.
这是防止污染最好的方式。
This is the most interesting film that i've ever seen.
这是我看过的最有趣的电影。
3、用法四：(4)当先行词是序数词或它前面有序数词修饰时,例子介绍如下:
This train is the last that will go to Suzhou.
这是去苏州的最后一趟火车。
What is the first American film that you have seen?
你看的第一部美国电影是什么?
用法五：(5)当先行词既有人又有物时,例子介绍如下:
Do you know the things and persons that they are talking about?
你知道他们在谈论什么人和什么事情吗?
1、当先行词指代物或者前面整句话的时候,定语从句中关系代词必须要用whih的情况如下：
用法一：(1)在非限制性定语从句中,只用 which,不用that。的情况如下：
Helen was much kinder to her youngest son than to the others,which, of course, made the others envy him.
海伦对她最小的儿子比对其他的儿子都要好,这当然让他们对他很嫉妒。
2、用法二：(2)当定语从句中的介词提前时,只用 which,不用that。的情况如下:
This is the house in which Lu Xun once Lived.
这是鲁迅曾经住过的房子
