With some technical problems to be solved, it may be a while _______ the system is put into use.
| A．when | B．after | C．since | D．before |
Only when _________________________.
| A．did he arrive the meeting began |
| B．he arrived the meeting began. |
| C．did he arrive did the meeting begin. |
| D．he arrived did the meeting begin. |
According to news reports, personal ____ of guns in the USA causes a lot of trouble.
| A．wealth | B．possession | C．matter | D．problem |
---Did you go to the cinema last night?
---Well, I had ____ to , but it was raining too hard.
| A．forgotten | B．expected | C．intended | D．wished |
Sorry, we are late,--our plane was _____ because of the heavy rain.
| A．held out | B．held on | C．held up | D．held back |
I’d like to have visited the Palace Museum, but something unexpected _______ to my father.
| A．had happened | B．happened | C．has happened | D．happens |