基面压实后应立即覆盖保温，表面能否采取撒盐水措施（）
A、允许
B、不允许
C、允许少量
参考答案：A
Don't go out to play. You ________ finish your homework first. [ ]
A. must
B. have
C. had
D. had to
（）不准拖带大型车。
