．Every possible means _______to prevent the air pollution, but the sky is still not clear．
| A．are being used | B．have been used |
| C．has been used | D．had been used |
---Is there ___ you don't understand?---I think ___ is quite clear.Thank you.
| A．something, nothing | B．anything, everything | C．nothing, anything | D．everything, anything |
The dishes my mother cooked ____. Everyone at the party liked it.
| A．tastes good | B．tastes well | C．taste bad | D．tasted good |
People in China used to keep records by putting a number of stones together, ___?
| A．usedn’t they to | B．did they | C．used to they | D．didn’t they |
--Can you tell me anything about the fire ___ last night?----I’m afraid, ____.
| A．theat broke out, very little | B．broke out, just a little | C．happened, only a little | D．taking place, a little |
We have been good friends for years.And we must ___ the friendship between us.
| A．go on with | B．keep on | C．keep up | D．remain |