题目内容：

9.You should have to stay behind if your homework__before five o'clock.
A.isn't done B.won't be done C.doesn't do D.wasn't done

优质解答

选A此句为if引导的条件状语从句结构;1．if从句用一般现在时,主句用一般将来时 If he runs he’ll get there in time.如果他用跑的,他就会及时赶到那儿.The cat will scratch you if you pull her tail.如果你拉猫的...