In 1948, three American scientists invented ____ transistor, which is ____ small electronic device to control an electric current.
| A．the; a | B．a; a | C．the; the | D．a; the |
Tired of her endless complaints, I walked out of the roomshe could open
her mouth.
| A．before | B．until | C．when | D．once |
-Do I have to bring my camera tomorrow afternoon?
-I think so. Wethe Botanical Garden then.
| A．are visiting | B．will be visiting |
| C．have visited | D．visit |
Every morning Jack's wife will stand before the mirror,herself before
leaving home.
| A．admired | B．being admired |
| C．to admire | D．admiring |
Arriving at the party hurriedly, we were disappointed to find that the bandplaying.
| A．stopped | B．will stop |
| C．had stopped | D．has stopped |
Tom may win the competition, he is likely to get into the national team.
| A．in that case | B．in which case |
| C．in what case | D．in whose case |