Which 和that同为关系代词，都可指物，并且有时会觉得用that 也可以，用which 也没错。但在哪些情况下是只能用that的呢？下面是小编为你带来的只用that的`定语从句 ，欢迎阅读。
一、注意先行词：
1）先行词是这样的不定代词：everything, anything, nothing, all, none, few, little, some（除something外）；
e.g: There seems to be nothing that is impossible to him in the world.
Note:先行词指人，偶尔亦可用关系代词who:
e.g: Any man that/who has a sense of duty won’t do such a thing.
2）先行词受every, any, all, some, no, little, few, much等词修饰。
二、先行词受如下词修饰：
1）被序数词修饰：
e.g: The first English letter that I learned was A.
2）被形容词最高级修饰：
e.g: This is the best movie that I have ever seen in my life.
3）被the very, the only, the first/last修饰
e.g: After the big fire, the old car is the only thing that he owns.
Note:先行词指人，偶尔亦可用关系代词who:
e.g: She is the only person that understands me.
三、先行词前有who, which等疑问代词：
e.g: Who is the man that is standing in front of the crowd?
四、先行词是人与（动）物：
e.g: Look at the man and his turtle that are walking up the street.
五，先行词是reason, way（方法），用that代替in which, for which, why，可以省略。
e.g: She admired the way (that) they solved the problem.
巧记口诀：
先行词是个不定代，the very/only/first; 有高、序，some, all, much, few；指物人，有了which/who。
