She let the children ______ to play instead of staying at home all the time.
| A．going out | B．went out | C．to go out | D．go out |
It’s already 10’clock. I wonder how it ____ that she was two hours late on such a short trip.
| A．came over | B．came out | C．came about | D．came up |
Many strange new means of transport have been developed in our century, the strangest of _____ being perhaps the hovercraft(气垫船).
| A．which | B．them | C．that | D．it |
___ the temperature might drop, coal was prepared for warming.
| A．To consider | B．Considered | C．Considering | D．To be considered |
We had a really bad time about six months ago but now things are ____.
| A．looking up | B．coming up | C．making up | D．turning up |
--- The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?
---____ my students have a try?
| A．Shall | B．Must | C．Will | D．May |