题目内容：

1-.It must have been hard word.
-Yes,it_____Dr.Yuan more than 20 years to develop the super hybrid rice.
A.takes B.has taken C.was taking D.took
2.--Did you go to Mrs.Smith's birthday party?
--Of course.Every boy and every girl in our class______.
A.has been invited B.have been invited C.was invited D.were invited

优质解答

1 it takes sb sometime/sth. to do sth. 做某事花费某人……it 做的是形式主语.
2. every +名词单数+every +名词单数做主语时,谓语动词用单数.我们班里的每个男孩和女孩都已经被邀请.