— How much difficulty did you have this problem?
— None．It’s quite easy.
| A．solve | B．solving |
| C．solves | D．to solve |
Avatar is an interesting film. I ______ it twice already.
| A．see | B．saw | C．have seen | D．will see |
— What are the kids doing?
— They ______ flowers in the garden.
| A．water | B．watered | C．have watered | D．are watering |
She ______ to her feet and ran out of the room just now.
| A．jumped | B．jumps | C．was jumping | D．will jump |
Ask John ______ here at 7 pm tomorrow.
| A．come | B．coming | C．came | D．to come |
The air in Beijing is getting much ______ now than a few years ago.
| A．clean | B．cleaner | C．cleanest | D．the cleanest |