A year can __________ twelve months.
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?
The one concern for parents and students is _______ the student pursues their university education in a foreign country, the student will not have the opportunity to establish social contacts in China.
After the quarrel, I tried all my best to fix the misunderstanding between us, but all my efforts seemed _____.
Failure hurts grown-ups and children___________, but it can make a positive contribution to your life once you learn to use it.