When I went to say goodbye to Ann, she ______ the piano.
| A．plays | B．played | C．has played | D．was playing |
There is no air _______ water on the moon .
| A．and | B．but | C．or | D．with |
They don’t know what ___________ the problem .
| A．to do | B．do | C．to do with | D．do with |
Don’t try to do everything at once. Take it a bit _______________.
| A．at times | B．at a time |
| C．at all times | D．at that time |
We __________ obey the traffic rules.
| A．must | B．have to | C．may | D．can |
What a ________ rain ! It has rained ______ since last night.
| A．heavily heavy | B．heavy heavily |
| C．hardly hard | D．hard hardly |