Not until all the fish died in the river ______ how serious the pollution was.
| A．the villagers did realize | B．the villagers realized |
| C．did the villagers realize | D．didn’t the villagers realize |
______________should be paid to our study,and only in this way ________make progress.
| A．Heart;we can | B．Mind;can we |
| C．Attention;can we | D．Notice;we can |
This machine is very easy . Anybody can learn to use it in a few minutes.
| A． operating | B． to be operating | C． operated | D． to operate |
Don’t handle the vase as if it _________ made of steel.
| A．is | B．were | C．has been | D．had been |
In order to find the missing child, the villagers___________ all they can in the past five hours.
| A．have been doing | B．did | C．do | D．had done |
With a lot of problems _________,the manager felt like a cat on hot bricks.
| A．solved | B．solving | C．to solve | D．being solve |