It’s said that corn was grown a lot in Tibet _______.
| A．in 17th century | B．in the 17th century |
| C．in 17 century | D．in the 17 century |
When ____ different cultures, we often p
ay attention only to the differenced without noticing the many similarities.
| A．compared | B．being compared | C．comparing | D．having compared |
we should exploit the Antarctic’s natural resources is open to discussion.
| A．What | B．Whether | C．If | D．That |
World Wide Web was invented in 1991 byEnglish scientist ,Tim Burners-lee.
| A．\; an | B．The; an | C．The; the | D．A; the |
What shall we use for power when all the oil in the world has ____ ?
A. given out B. put out C. held up D used up
-----Could you do me a favor and take these books to my office?
-----Yes, _____.
| A．for pleasure | B．I could | C．my pleasure | D．with pleasure |