They _____ on the little professor, but it led to his fierce criticism on us.[ ]

Now there is a danger ________ the ground may fall in under the heavy traffic.

The Chairman of the National Table Tennis Committee is _____ the gold medal, the silver medal and thebronze medal to the winners of the game ______ [ ]

I shall take you back to Beijing _____ you are well enough to travel

It is years I last visited the mine I wonder how things are getting on there