Smile to the world, the world will smile back to you.
A. but B. or C. and
If your homework , you may watch TV for half an hour.
A. is finished B. will be finished C. has finished
— What can I do to save energy?
— You ought to the electricity when you leave a room.
A. shut off B. give up C. take away
Mr. Brown to Taiwan for his business the day after tomorrow.
A. flies B. is flying C. flying
There is no that the Internet plays an important role in the modern life.
A. question B. doubt C. problem
More and more trees were cut down. , many animals are dying out.
A. So that B. As a result C. In order to
