初中英语知识点：定语从句中只能用which

　　定语从句中只能用which，不能用that的几种情况：

　　1. 在介词后面的关系代词用which而不能用that。即“介词+which(代物)” 例如：

　　The picture for which he paid $1,000 was once owned by a duke.

　　他花了1000美元买下的画曾为一名公爵所拥有。

　　The building in which Han Mei studied was very old.

　　韩梅在里边学习的那幢大楼很旧。

　　2. 在非限定性定语从句中不能用that。例如：

　　Crusoe's dog, which was very old now, became ill and died.

　　克鲁索的狗，现在已经很老了，病死了。