Most air pollution is caused by the burning of _________ like coal, gas and oil.
It was easier to move about___ the fringe of the crowd.
So far, several ships have been reported missing _____the coast of Bermuda Island.
the trees in that thick forest are so dose together that there is hardly any room to move____ them.
The speech by the mayor of Shanghai before the final voting for Expo 2010 is strongly impressed ____ my memory.
It is raining ___ .