1 . Directions: Fill in each blank with a proper word chosen from the box. Each word can only be used once. Note that there is one word more than you need.

A. bay     B. target       C. exhibit       D. impressive       E. unbothered       F. fertile G. unsuspecting       H. pinpoint       I. scratch       J. issue       K. concentrations

Are You a Mosquito Magnet?

You’re trying your best to enjoy an evening cookout, but a constant swarm of mosquitoes follows you from grill to poolside. The threat? A pierce to your skin, leaving behind an itchy red welt and possibly even a serious illness. As you hit madly at the pests, you notice that others seem completely     1    . Could it be that mosquitoes prefer to bite some people over others?

The short answer is yes. Mosquitoes do     2     blood-sucking preferences, say the experts. “One in 10 people are highly attractive to mosquitoes,” reports Jerry Butler, PhD, professor at the University of Florida. But it’s not dinner they’re sucking out of you. Female mosquitoes - males do not bite people - need human blood to develop     3     eggs. And apparently, not just anyone’s will do.

Who Mosquitoes Like Best?

Although researchers have yet to     4     what mosquitoes consider an ideal hunk(大块)of human flesh, the hunt is on. “There’s tremendous amount of research being conducted on what compounds and odors people exude(散发出)might be attractive to mosquitoes,” says Joe Conlon, PhD, technical advisor to the American Mosquito Control Association. With 400 different compounds to examine, it’s an extremely laborious process. “Researchers are just beginning to     5     the surface,” he says.

Scientists do know that genetics account for an overwhelming 85% of our susceptibility to mosquito bites. They’ve also identified certain elements of our body chemistry that, when found in excess on the skin’s surface, make mosquitoes swarm closer.

“People with high     6     of steroids(类固醇)or cholesterol(胆固醇)on their skin surface attract mosquitoes,” Butler tells WebMD. That doesn’t necessarily mean that mosquitoes prey on people with higher overall levels of cholesterol, Butler explains. These people simply may be more efficient at processing cholesterol, the byproducts of which remain on the skin’s surface.

Mosquitoes also     7     people who produce excess amounts of certain acids, such as uric acid, explains John Edman, PhD, spokesman for the Entomological Society of America. These substances can trigger mosquitoes’ sense of smell, tempting them to land on     8     victims.

But the process of attraction begins long before the landing. Mosquitoes can smell their dinner from a(n)     9     distance to up to 50 meters, explains Edman. This was no good news for people who emit large quantities of carbon dioxide. Luckily, there are chemical-based mosquito repellents(驱虫剂)and the soybean oil-based repellent that can help to keep the bite at     10    .