【单选题】
There are four reading passages in this part.Each passage is followed by five
questions. For each question there are four suggested answers markedA,B, C、and D、Choose one best answer and blacken the corresponding letter on theAnswer Sheet.Passage One What’s the best way to protect a tender, green seedling from the hungry stomach of deer? Give the seedling bad breath!The same chemical that gives people bad breath after they have eaten garlic can save small trees from being eaten by animals.A、kind of chemical selenium(硒), which is also found in garlic, is planted in the soil near a young tree. The tree’s roots absorb the selenium which is then carried to the leaves.From there the selenium is used to form a chemical called dimethyl selenide (乙烷 硒化物)—the same chemical made in the human mouth after eating garliC、As deer wander around looking for food, they smell the seedlings’leaves and leave the plants alone.
The selenium is important. Why?Because each year deer eat millions of dollars’
worth of trees farm seedlings.So far, selenium has been tested only onDouglas fir (枞树) seedlings, but researchers think they could protect fruit trees and garden plants, too.