There was a knock at the door .It was the second time someone ____me that evening.
A had interrputted ,B would have interruptted ,C to have interruptted. 为什么不能用B啊？
The course normally attracts 20 students per year,____up to half will be from overseas.
A in which,B for whom ,C with which ,D of whom 为什么A不可以？这是个限定性状语从句啊。
THE physicist has made a discovery,_____ of great importance to the progress of science and thecnoloyg.
A which I think is ,B which I think it is.B错在那里了？which不是不能引导宾语从句吗？他能做句子成分吗？
參考答案:1。B是虚拟语气。
2。后面的定语从句是修饰students的，不是year.
3.这也是个定语从句，whiich 指代的是DISCOVERY。（你可以先把I think 拿掉就看出来了）