Parents shouldn’t be too ______________ towards their children; they should let them be more independent.
| A．genuine | B．protective | C．close | D．outspoken |
As is well known, carelessness and irresponsibility _______ many deadly accidents.
| A．lead to | B．result from | C．contribute to | D．result in |
They ___________ for two hours
| A．is working | B．worked | C．have been working | D．had worked |
Taiyuan，a city in North China，was struck by a heavy snowfall last week，________serious traffic problems.
| A．to face | B．faced | C．facing | D．having faced |
It was not until the beginning of the twentieth century________to explore space.
| A．did man begin | B．when man began |
| C．that man began | D．then man began |
A notice was________in order to remind the students of the changed lecture time.
| A．sent up | B．given up |
| C．set up | D．put up |