20. _______, English is one of the most important subjects.
| A．It is known to all that | B．As is known to all that |
| C．As we know | D．As it is known to all |
When you arrive in Nanjing, tell me the address of the company _ you’ll work and l’11 drop you a line.
| A．that |
| B．which |
| C．what |
| D．where |
--- What happened? I called you several times yesterday evening, but I couldn’t get through.
--- Sorry, my sister and I on the phone all the time．
| A．talked |
| B．have talked |
| C．were talking |
| D．have been talking |
If Liu Xiang injured, we might have seen his wonderful performance at the London Olympics.
| A．didn’t get |
| B．hasn’t got |
| C．wouldn’t get |
| D．hadn’t got |
tablet computers like Apple’s iPad just before bed, a research says recently, can lead to poor night’s sleep.
| A．Using |
| B．Used |
| C．To use |
| D．Use |
--- Do you know why Michael resigned from the board?
--- He held out for higher wages, but was in the end.
| A．put down |
| B．broke down |
| C．cut down |
| D．turned down |