The first step towards ________(protect)the environment is to try to throw away less rubbish．

Our Maths teacher ________(prepare)the new lesson with other teachers in the office from 2 to 4 yesterday afternoon．

The policeman said that he ________(see)a Young Pioneer help an old woman cross the road the day before．

Many changes ________(take)place in our daily life since the invention of the computer．

Today, to hold the Olympic Games ________(consider)as a rich prize for a country．

Playing computer games is delightful, but ________(spend)too much time on it may do harm．

On May 12, 2008, sichuan ________(hit)by a strong earthquake which killed many people and distroyed many buildings．

We should think about what we can do ________(keep)animals and plants from becoming endangered．

It was a pity that you ________(not attend)the meeting last Friday afternoon．

I’ll tell our monitor the good news as soon as he ________(come)back to school．