| With more factories and traffic, the air of the city is much dirtier than _____ of the suburbs. |
A. it B. that C. one D. those |
| When my hand touched the letter in my pocket,I realized that I had forgotten _____ it. |
A. to post B. to have posted C. posting D. having posted |
| According to recent reports, one of the rare animals, _____ crocodile, is in _____ danger of dying out. |
A. a; the B. /; a C. /; the D. the; / |
| — Excuse me. Is this the right way to the Horticultural Expo? — Sorry, I am not sure. But it _____ be.? |
A. might B. will C. must D. can |
| You can see as far as the Taibai Mountains on top of the building _____ the sky is clear. |
A. when B. where C. though D. because |
| The question came up at the meeting ______ we had enough money for our research. |
A. if B. what C. that D. whether |
| Computers have _____ many changes in the workplace. |
A. heard about B. known about C. brought about D. cared about |
| They will fly to Beijing, _____ they plan to stay for two or three days. |
A. which B. where C. there D. when |