It is high time, I think, that you got down to ______ something in class.
| A．do | B．did | C．doing | D．does |
The scientists are able to ____________ accurately when the spaceship will reach the moon.
| A．accumulate | B．calculate | C．appoint | D．estimate |
－Can I pay the bill by check?
－Sorry, sir. But it is the management rule of our hotel that payment ______ be made in cash.
| A．shall | B．need | C．will | D．can |
The driver got out of the car_______it caught fire.
| A．directly | B．that | C．unless | D．until |
__________twice a year, whether it is a car or bus or a truck, is the rule that every driver must obey in this city.
| A．Examining | B．Examined | C．Being examined | D．Having been examined |
Peter was fired again. He really didn’t know _____ went wrong.
| A．why | B．what | C．where | D．that |