题目内容：

Research finds out why some people are constantly under attack from the bloodsucking insects while others walk free.

For those unfortunate enough to feature highly on the mosquito hit list, summer nights can be synonymous with mosquito bites. Yet others hardly ever get bitten. So how do the bloodthirsty insects select their victims?

The insects’ tastes may seem arbitrary. However, research shows that when mosquitoes make their choices between potential victims, it all comes down to scent (气味).

“Mosquitoes are attracted by carbon dioxide and heat, which everyone gives off. But mosquitoes are also attracted by certain scents,” says Karl-Martin Vagn Jensen, the head of research at the Department of Agricultural Science at Arhus University.

According to Jensen, it has not yet been confirmed exactly what the scents in question are. But research does indicate that some scents are more attractive to mosquitoes than others.

“All the lab employees rubbed petri dishes (培养皿) against their stomachs. In that way, their scents were put on the dishes, which were then put in a container full of mosquitoes,” he says. “The mosquitoes repeatedly landed on some of the petri dishes, but didn’t go anywhere near the others.”

Perhaps taking inspiration from popular fiction, there are also those who consider garlic as an excellent repellent (驱虫剂) against the winged bloodsuckers. According to the researcher, this strategy may not be entirely fruitless. “As far as I know, there is no scientific proof that eating garlic works. But there may be something to the theory that it’s possible to mask scent with garlic,” he says. The only reliable method of protection against mosquitoes is to use repellents that are sold over the counter. It contains some smells that can confuse the mosquitoes. When the mosquito comes closer, it uses smell, heat and carbon dioxide to decide whether to bite. But if it is confused by a repellent, it will never get that far.

1.Which of the following can best replace the phrase underlined in Paragraph 2?

A. Be equal to.    B. Be accessible to.    C. Be harmful to.    D. Be beneficial to.

2.What can we infer about the scents attracting mosquitoes?

A. Mosquitoes can be attracted by various scents.

B. Some kinds of scents appeal to mosquitoes in particular.

C. The lab employees use petri dishes to deposit their scents.

D. Mosquitoes are arbitrary when it comes to different scents.

3.What is the main idea of the last Paragraph?

A. A new strategy is used in researching repellents.

B. Garlic is considered to be an excellent repellent.

C. Using repellents is an effective way against mosquitoes.

D. The inspiration against mosquitoes is from popular fiction.

4.Where is the text most probably taken from?

A. Science fiction.    B. A biography.    C. A medical report.    D. A research paper.