How can they expect to learn anything_________they never listen?
| A．when | B．until | C．unless | D．though |
Only when______senior high school_________to show a great interest in poems.
| A．did I enter; did I begin | B．did I enter; I began |
| C．I entered; I began | D．I entered; did I begin |
— Why are you still here? Everybody has gone to attend the lecture by the president.
— Oh, I__________about it!
| A．wasn’t informed | B．hadn’t been informed | C．haven’t informed | D．didn’t inform |
Mr. Duncan raised an unnecessary question he then failed to find an answer.
| A．to which | B．for which | C．with which | D．by which |
____________caused the accident is still a mystery.
| A．How | B．What | C．That | D．Where |