A salty diet may increase the risk of stomach cancer ________ 10 percent, South Korean researchers found in a study of more than 2 million people.
| A．at | B．to | C．by | D．for |
What's your opinion of Mr．Li's request that we ______ spend half an hour reading English aloud every morning?
| A．would | B．should | C．must | D．could |
The United Nations are evaluating the damage caused in Haiti earthquake, while in Chile the government itself ______ the lead role．
| A．is taking | B．was taking | C．took | D．had taken |
Put yourself in situations where you're forced to communicate in English, ______ you'll see more progress over time.
| A．until | B．or | C．but | D．and |
Tom's mother kept telling him that he should work harder, but ______didn't help．
| A．he | B．which | C．it | D．one |
As Susan stared at ______ piles of plastic in her recycling bin, ______ strong sense of responsibility made her stick to her recycling work.
| A．不填；不填 | B．不填; a | C．the ; a | D．the; the |