—My son is addicted to drugs. He isn’t hopeless, is he?
—Yes, _____ he mends his ways and starts all over.
| A．if | B．when | C．even if | D．unless |
The World Wide Fund for Nature is an organization_____aim is to protect wildlife.
| A．who | B．where | C．which | D．whose |
A container weighs more after air is put in,_____proves that air has weight.
| A．as | B．it | C．that | D．which |
I’ll take you to a shopping center nearby_____you may buy all_____you need.
| A．that; that |
| B．which; that |
| C．where; which |
| D．in which; 不填 |
Do you know the reason_____she didn’t attend her boyfriend’s birthday party yesterday?
| A．why | B．which | C．for that | D．for why |
What especially impressed us was the way_____the girl studied foreign languages.
| A．不填 | B．which | C．by which | D．how |