问题

ition to the farming they ______ since the1990s, the Smiths have started a small business.

A:have done
B:had been done
C:were doing
D:have beendoing

正确答案是：

同类题型

The teacher asked the students ________

Could you tell me____a meeting in Guangzhou next week

The supermarkets____open until late every evening, which provides us much convenience.

下列词语中加横线字读音完全正确的一项是（）

Please remain _________ until the plane hascome to a complete stop.