All flights because of the storm, they had to wait in the hall.
| A．have put off | B．were put off |
| C．have been put off | D．having been put off |
Don't leave your work half _____.
| A．being done | B．doing | C．to do | D．done |
Any student,who is thougnt ______ the rules, for example, by cheating, has _____ before a student court.
| A．to have broken; to appear | B．to break; to get |
| C．broken; taken | D．to break; to be taken |
Prices of daily goods _____ through a computer can be lower than store prices.
| A．buying | B．bought | C．are bought | D．been bought |
______ in the chimey for five hours, the thief looked very pale and tired.
| A．Having been trapped | B．Being trapped |
| C．trapping | D．Having trapped |
The crowd is too noisy, but anyway I have to make myself ______ to them because the news is so important to them.
| A．known | B．understood | C．heard | D．known |