We all know trees play an important role in _______up the air.
| A．clean | B．cleaning |
| C．cleaned | D．Cleans |
-How many ____________did you do yesterday?
-Six Patients were ____________on.
| A．operation,operate | B．operate,operation |
| C．operations ,operated | D．operations,operate |
Nothing will prevent us_________our dreams.
| A．achieve | B．to achieve |
| C．achieving | D．achieve |
-Are you going to Shanghai for vocation?
-Yes.We want you to_______us with some information about it.
| A．offer | B．give | C．show | D．provide |
All of us find_______necessary to take exercise every day.
| A．this | B．it | C．that | D．them |
My parents warn me __________too many computer games.
| A．not play | B．not to play |
| C．to not play | D．don’t play |