The computer, help we human beings have stepped into the information age, should be regarded as one of the most important inventions in the 20th century.
| A．which | B．whose |
| C．with its | D．with whose |
We should consider the students' request __________ the school library provide more books on popular science.
| A．that | B．when | C．which | D．where |
—How much do you know about the 3D film technology?
_ A little. Not until the hot movie Avatar __________ some about it.
| A．did I see ； did I begin to learn |
| B．I saw;I began to learn |
| C．I saw;did I begin to learn |
| D．did I see；I began to learn |
Some of you may have finished unit one. __________ you can go on to unit two.
| A．If you may | B．If you do | C．If not | D．If so |
He observed a stranger __________ around the store at midnight.
A, wandering B. to wander
C. wander D. to be wandering
My sister, an inexperienced rider, was found sitting on the bicycle __________ to balance it.
| A．having tried | B．trying | C．to try | D．tried |