--- How long have you ___________? --- It’s about ten years since we ___________.
— I put him down for a well-educated man.—______ ?— I mean that he's a well-educated man.
The silence of the library is sometimes broken by a sudden cough or the sound of pages______.
Wang Pin is an advanced worker in our company. He _______ for four years in Yangzhou University.
When it______ air pollution, Beijing faces the three “C” s-----cars,coal and construction,which lead to Beijing's thick air pollution.
______ it have been the failure to pick up directions from the ground control that caused the air crash?