It was not until the early 1950s ______most tape recorders began using plastic tape as they do today.
| A．when | B．which | C．that | D．Before |
______ the Internet is bridging the distance between people, it may also be breaking some homes or will cause other family problems.
| A．When | B．While | C．If | D．As |
The ship had 500 passengers _______.
| A．on board | B．on the board | C．on a board | D．on boards |
—I’ll come to see your performance at 9:00 tomorrow evening.
—But by then my performance will have ended and I ______ reporters in the meeting room at that time.
| A．will meet | B．will be meeting | C．are going to meet | D．am meeting |
_______, my heart ______.
| A．On hearing the sad news, sank | B．Hearing the sad news, dropped |
| C．At the sad news, fell | D．When I heard the sad news, sank |
Mr. Smith suggested the problem worth paying attention ______ at the meeting.
| A．to be discussed | B．to being discussed | C．being discussed | D．be discussed |