the big crowd coming towards him, he started to run down the hill, but ______ and went down on his hands and knees in the melting snow.

Your sister must be helping the little girl with her homework, _______ ?

Mary and I see each other ________, but not as often as we used to.

twice a year, whether it is a car ,a bus or a truck, is therule that every driver must obey in this city.

shall be in china for three weeks. Can you make some suggestions _____ what I should see?