英语 疑问词加不定式

问题描述:

英语 疑问词加不定式
There are so many kinds of tape-recorders on sale that I can't make up my mind which to buy
which to buy做从句的什么成分,定语还是宾语补足?为什么?

应该为宾语例如 make one's mind=to decide sth
Have you made up your minds where to go for your holiday?