His father, who is said to be teaching in Australia, ____ in Nanjing University for more than 10 years.
| A．has worked | B．had worked | C．worked | D．has been working |
Mr. White will come to the party on Sunday, _______ he promised to every one of us.
| A．when | B．that | C．what | D．which |
_______ that caused him to serve dinner an hour later than usual.
| A．It was we being late | B．It was our being late |
| C．It was we were too late | D．It was because we were late |
China _______ a sharp increase in the number of aged people over the past decade.
| A．sees | B．saw | C．has seen | D．will see |
Mr. Frank asked me a question _______ I could go with him to _______ he called the Treasure House the next week.
| A．that; which | B．whether; that | C．whether; what | D．that; where |
—The terrible accident is under investigation.
—Actually, quicker action ______ those workers trapped in the mine.
| A．might have saved | B．must have saved | C．should have saved | D．could have saved |