Not until I began to work ____ realize how much time I had wasted.
| A．didn't I | B．did I | C．I didn't | D．I |
The engineer spoke highly of the government’s efforts, ____ he owed his safe return from Libya.
| A．through which | B．to which | C．with whom | D．for whom |
—Why did you leave without a word of warning to John?
—But what _____ otherwise? He never listens to me.
| A．could I have done | B．would I do |
| C．must I have done | D．should I do |
Mary often stays up, reviewing her lessons, books___ all over the desk.
| A．spreading | B．spread | C．are spreading | D．to spread |
—Look, the paint is starting to come off ____ the wall is damp.
—Well, we'd better have the wall repainted some day.
| A．when | B．where | C．if | D．once |
If you ___ stick to the unrealistic approach, the worse result will be waiting for you not far ahead.
| A．will | B．may | C．must | D．can |