The farmers expanded their production to meet the increasing demand _____ locally grown food.
| A．for | B．in | C．of | D．to |
31. —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 |
30. In some countries, treatments for A(H1N1) flu were neither ________ nor effective, and many patients died because of infection.
| A．critical | B．scientific | C．necessary | D．Special |
29.For English teachers ________ a more effective role in teaching, they must make every effort to raise students’ cross-cultural awareness.
| A．to play | B．playing | C．having played | D．Play |
28. —Did you hear Tom was criticized for his spelling mistakes in his English composition?
—Yes, but a more careful person ________ so many mistakes.
| A．wouldn’t make | B．needn’t have made |
| C．shouldn’t make | D．wouldn’t have made |
27.If you ________ to something different, for example to a different system, task, or subject of conversation, you change to it from what you were doing or saying before.
| A．switch | B．appeal | C．submit | D．adapt |