They will fly to Washington, ______they plan to stay for two or three days.
| A．which | B．where | C．there | D．when |
— Show me your permit, please.
—Oh, it's not in my pocket. It_______________.
| A．might fall out | B．could fall out |
| C．should have fallen out | D．must have fallen out |
I tried hard to get some information about the new technology out of his mouth, but he remained____________.
| A．quiet | B．secret | C．silent | D．calm |
The queen will visit the town in May, she will open the new hospital.
| A．when | B．then | C．while | D．but |
Nothing__________ after the terrible fire which had been caused by someone smoking in bed.
| A．left | B．was remained | C．remained | D．continued |
___________ with the size of the whole earth, the highest mountain doesn't seem high at all.
| A．When compared | B．To compare |
| C．While comparing | D．It compared |