21.  It really proves its usefulness in emergencies.

22.  Three years in a senior school can prove it .

23.  Others try to prove that money is the source of crimes.

24.  We looked into our bags, and the girl's words proved to be true.

25.  it proved that you have suceeded in half.

26.  Smill proved you are good manner , honesty, and gentle.

27.  Many example had proved that the exercise without intermittent will make a good health for you.

28.  The history of our country in the past before 1978 have proved this.

29.  At the same time, the people's living conditions have proved than before.

30.  Because they like challenge, they want to proved that they can do any work if they like.