修饰时间的定语从句，一起来看看吧。
区别的关键在于time放入定语从句中,是做句子的时间状语还是主语/宾语等名词性成分.
1. 如果定语从句缺少时间状语,一般用when
如：There was a time when the song was popular.
a time在从句中做时间状语
2. 如果定语从句缺少主语/宾语等名词性成分,则一般用which/that,有时还可以省略.
如：I‘ll never forget the time (which/that) I spent with you.
the time在从句中充当spent的宾语
另：下列句型中固定用that
This/It + is/was + the first/second... time +that从句
It be (high/about) time that从句
附：是不是所有的定语从句都要跟紧跟在先行词后面?
由于修辞和结构的需要定语从句和它所修饰的'先行词常常被状语和谓语所分割.
例如：
e are many thousands of stars in the sky that are like the sun.
在太空中有成千上万的象太阳般的星星.
状语in the sky分割了定语从句和它的先行词stars,定语从句的先行词不是the sky,而是stars.
you remember one afternoon ten years ago when I came to your house and borrowed a diamond necklace?
你还记得吗,十年前的一天下午,我来到你家,找你借了一条钻石项链?
when引导的定语从句的先行词是one afternoon,它们被ten years ago所分割.
3.A new master will come tomorrow who will teach you German.
明天,新（男）老师将来教你德语.
先行词A new master 和定语从句who will teach you German被谓语,状语will come tomorrow所分割.
