we have two rooms to live in,but we haven't decided which one to choose.

问题描述:

we have two rooms to live in,but we haven't decided which one to choose.
which one to choose.为什么不用to choose which one?

这个语法结构叫“疑问词 + 不定式”,该结构相当于一个名词(短语),在句中充当主语/宾语/表语等成分.如果是疑问代词,则疑问词一般充当不定式中某个动词或介词的宾语.如:I don't know what to do.what to do 做know...