The factory was built in a secret place, around _____ were high mountains.
| A．where | B．it | C．that | D．Which |
I was about to tell everyone the truth ______ she turned up.
| A．while | B．when | C．as | D．till |
Helen is on time for everything. How ______ it be that she was late for such an important interview?
| A．might | B．can | C．must | D．may |
While you are enjoying yourself in Beijing this time tomorrow, I __my mother do housework at home.
| A．am helping | B．will help | C．would help | D．will be helping |
The e-mail, as well as the telephone, ______ an important part in daily communication.
| A．is playing | B．have played | C．are playing | D．play |
Jumping out of ______airplane at ten thousand feet is quite _____exciting experience.
| A．/ ；the | B．/ ；an | C．an；an | D．the ; the |