a) 引導非限定性定語從句時。例如:
(錯)The tree, that is four hundred years old, is very famous here.
b) 介詞后不能用。例如:
We depend on the land from which we get our food. 我們依賴土地獲得食物。
We depend on the land that/which we get our food from.
2) 只能用that作為定語從句的關系代詞的情況
a) 在there be 句型中,只用that,不用which.
b) 在不定代詞,如:anything, nothing, the one, all, much, few, any, little等作先行詞時,只用that,不用which.
c) 先行詞有the only, the very修飾時,只用that.
d) 先行詞為序數(shù)詞、數(shù)詞、形容詞最高級時,只用that.。
e) 先行詞既有人,又有物時。例如:
All that is needed is a supply of oil. 所需的只是供油問題。
Finally, the thief handed everything that he had stolen to the police. 那賊最終把偷的全部東西交給了警察。
更多定語從句講解 ,語法學習 http://42bites.com/show-113-328135-1.html