问题

There are several theories about why dinosaurs suddenly died out, one of which says their disappearance _______ by the climate change.

A:might have caused
B:should have caused
C:might have been caused
D:should have been caused

正确答案是：

同类题型

－I hear you’ve got a new pen pal. I wonder ________.－Oh, he is of medium build with short curly hair from the USA.

If it ______tomorrow, we’d stay at home

Usually, we like to _________ before doing sports so that we can’t hurt during the sports.

Could you tell me _______yesterday— Because my bike was broken on my way here.

I’m sorry, but I didn’t mean to keep you waiting here for a long time. Can you _______ me