22. Tom, you play the violin so well. But I ______ you can play the violin.
| A．didn’t know | B．don’t know | C．hadn’t known | D．haven’t known |
While the police have already done a lot of investigation, much evidence _____.
| A．is remaining to be confirmed | B．remained to be confirmed |
| C．is remained to be confirmed | D．remains to be confirmed |
_____ on everyday practice, progress in English is a goal which can be achieved．
| A．Based | B．Basing | C．Having based | D．Being based |
Look out! Keep away from the house, _____ the roof is under repair．
| A．whose | B．which | C．of which | D．where |
．You’d better get the problem solved as soon as possible ______ it becomes out of control．
| A．when | B．before | C．since | D．unless |
—Happy Birthday, Ken! Did you invite Jason?
—Yes, but he _____ a meeting in New York otherwise he wouldn’t be absent from my birthday party．
| A．is attending | B．has attended | C．was attending | D．attended |