–Look! A man is cutting a tree on the moon. --It ______ be true. The teacher said there is no air on the moon.
—Mum, _________ I play football? —Yes, you can. But you should finish your homework first.
It’s snowing all day, so mybrother ______ stay at home. A.must B.have to C must to D.has to
The two boys are fighting _______ each other.
When will the Greens arrive _______ Nanjing.
My mother arrives late _______ work because of the heavy rain.