_________ you may have, you should gather your courage to face the challenge.
| A．However a serious problem | B．What a serious problem |
| C．However serious a problem | D．What serious a problem |
When I opened the door, I found my father sitting in his chair, completely __________ in the humorous stories he was reading.
| A．absorbed | B．losing | C．attracted | D．addicted |
Before __________him, Icalled him __________.
| A．visiting；in advance |
| B．visit；in advance |
| C．visiting ； advance |
| D．visit； advance |
In the past 100 years many species, as a result of human destruction to nature，__________ and many more __________ now.
| A．have disappeared； are disappearing |
| B．disappeared；are disappearing |
| C．have disappeared；disappear |
| D．are disappearing；disappear |
Johnson held a party，__________ he invited all hisfriends.
| A．for whom | B．to whom | C．to which | D．from which |
—Where did you get to know her?
—It was on the farm __________ we worked.
| A．that | B．there | C．which | D．where |