At school, some students are active __________ some are shy, yet they can be good friends with one another.
| A．while |
| B．although |
| C．so |
| D．as |
Then moment _________ Mary will always remember is _________ Mr．Black gave her a lot of valuable advice on how to improve her writing．
| A．when; that | B．that; that | C．that; when | D．when; where |
The problem was very difficult to handle．We worked it out，__________ ．
| A．too | B．yet | C．although | D．though |
—Can I pay the bill by check?
—Sorry，sir．But it's the management rules of our hotel that paymentbe made in cash．
| A．shall | B．need | C．will | D．can |
Helen was much kinder to her youngest child than she was to the others，，of course，made the others jealous．
| A．who | B．that | C．which | D．what |
is known to us is that tobacco contains nicotine and other harmful products，so you should give up smoking．
| A．As | B．It | C．What | D．Which |