Our environment is getting worse than before. –You’re right. But thanks to Earth Day, people have done more and more useful things to protect the earth since Earth Day         .

A  is started     B  was started      C  has started

 I want to be a doctor. –Doctors         in every part of the world, I think.

A need      B  are needed     C  are needing      D  will need

 Do you believe there are aliens? –I ‘m afraid not. I don’t think aliens         in space.

A  can find  B  can be found  C  can be founded  D  can’t be found

Our environment is getting worse than before. –You’re right. But thanks to Earth Day, people have done more and more useful things to protect the earth since Earth Day         .

A  is started     B  was started      C  has started

 I want to be a doctor. –Doctors         in every part of the world, I think.

A need      B  are needed     C  are needing      D  will need