_____ I admit that the problems are difficult , I don’t agree that they cannot be solved.
| A．While | B．Suppose | C．Because | D．as though |
—Could I use your computer for a few moments, please?
—______. I’m not using it myself.
| A．Come on | B．It depends | C．Go ahead | D．That’s right |
______many times, he finally understood it.
| A．To tell | B．Telling | C．Having told | D．Having been told |
Many children, __parents are away working in big cities, are taken good care of in the village.
| A．that | B．whose | C．which | D．whom |
—What’s that noise?
—Oh, I forgot to tell you. The new machine ________.
| A．was tested | B．will be tested | C．is being tested | D．has been tested |
. E-mail, as well as telephones, ________ an important part in daily communication.
| A．is playing | B．have played | C．are playing | D．play |