Question

定语从句若是缺失成分就一定不能用that对吗?

Answer 1

that在定语从句中做主语、表语或宾语,作宾语时可省略.
必须用that的情况：
先行词有人又有物
先行词有形容词最高级修饰
先行词是不定代词
先行词有不定代词修饰
以who,which开头的问句
先行词有the very,the same ,the last等词修饰
先行词有序数词,数词修饰时.
关系词在定语从句中做表语时
不能用that的情况：
介词+关系词
非限定性定语从句
举例：
Is this the book that you borrowed in the library?
这是你在图书馆借的那本书吗?
Who that break the window should be punished．
谁打碎了窗户都要受到惩罚．
All that is needed is a supply of oil.
所需的只是供油问题.
Finally,the thief handed everything that he had stolen to the police.
那贼最终把偷的全部东西交给了警察.