定语从句牵涉的内容比较多，今天主要讲先行词为“物”时，引导词用that不用which的几种情况：
1.先行词是all，nothing，something，everything，few，little，much等不定代词时。
2.先行词被the same，little，all等词修饰时。
3.先行词是序数词，形容词最高级，或者被它们修饰时。
4.先行词既有人又有物时。
例句：
1.He bought something that his wife likes.
2.The little problem that we meet in our life may be inspirations for great inventions.
3.It is the best book that I have ever read.
4.I have forgot all the people and things that once were very important to me.
