—Excuse me, what time __________ the train __________ ?—At 8:10 tomorrow morning. A. does ;pull out B. do ;pull in
There is a new problem involved in the popularity of private cars _______ road conditions need _______.
It is pretty well understood __________controls the flow of carbon dioxide in and out the atmosphere today.
____is certain is ___prevention is more important than treatment .
_______has recently been done to provide more buses for the people ,a shortage of public vehicles remains a serious problem .
The experience of the Chinese nation attests to a truth____ a nation loses in times of disaster will be made up for by her progress