题目内容：

选什么怎么做包括什么语法点
who repaired the computer and when do you know?
i'm not sure who repaired it but i'm sure he______ yesterday.
A repaired it
B had repaired it
C had it repaired
D had it to be repaired

优质解答

选C这句的前半句说,我不清楚是谁修的,如果选A,那么后半句的意思是,我确定他是昨天修的,主语是他,意思就是他本人修的,这样的话,前半句与后半句是自相矛盾的.而选C,he had it repaired 的意思是,他让别人修的（非他本...