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 |
. I regret _______ you that we are unable to offer you employment.
| A．informing | B．having informed | C．to inform | D．to informing |
. You had better get a doctor _______ your bad tooth.
| A．pull out | B．to pull out | C．pulled out | D．pulling out |
. The matter had better _______ as it is.
| A．leave | B．being left | C．leaving | D．be left |
. He was so foolish _______ his car unlocked.
| A．to leave | B．that leave | C．as to leave | D．for him to leave |
. Almost everyone fails _______ the driving test on the first try.
| A．passing | B．to have passed | C．to pass | D．in passing |