Computers can do nothing．But once ________ what to do, they show extraordinary power to do a great deal．

A．to program

B．being programmed

C．programmed

D．having programmed

________ twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city．

A．Being examined

B．Examining

C．Examined

D．Having been examined

What a pity! ________ joined in the party, I would have met my old friend．

A．lf I have

B．Had I

C．I had

D．Have I

Today's homework was easy ________ so I finished it quickly and went out to play．

A．to be done

B．done

C．doing

D．to do

Don't you think ________ of great importance that we should keep fit by taking exercise regularly?

A．this

B．that

C．which

D．it

The news was a terrible blow to her, but she ________ the shock soon．

A．got out

B．got over

C．got off

D．got through

When he goes out, he often wears sunglasses ________ nobody can recognize him．

A．so that

B．now that

C．in case

D．as though

The desks in our classroom are so close together that there is not enough room to move _________ them．

A．between

B．in

C．across

D．over

________ travelling expenses rising a lot, we had to change all our plans for the tour．

A．As

B．By

C．Since

D．With

Professor Wang ________ in our school till next Sunday．

A．will have stayed

B．has stayed

C．is staying

D．stayed