There is a crowd of people in front of the house over there. What do you suppose _____ there?
He moved to a big city to try his __________.
You can only tell the news to Tom,Jack and Bill,and __________ it should be kept.
I’m afraid none of us can __________ the machine that has been imported from abroad.Which of the following is wrong?
In Britain,sales of cigarettes have been reduced __________ 30% in the past ten years.
Whenever you are to walk on the ice,__________ that it is solid and safe enough.