A
Over the past 20 years, scientists studying monarch butterflies have noticed that the number of monarchs has dropped by about 90 percent. But help may soon be on the way for these brightorangeandblack butterflies.
Recently a petition (请愿) was sent by the Center for Biological Diversity, the Center for Food Safety, and the Xerces Society to the U．S. Fish and Wildlife Service, who announced it would take a year to decide whether the butterflies should be considered an endangered or a threatened species. By officially labeling monarchs as endangered, the government can then carry out specific plans to help increase the population of monarch butterflies.
Monarch butterflies are known for their impressive, almost 3,000mile migration each fall. When the weather starts to get cooler, the butterflies move from summer habitats in Canada and the northern U．S. to warmer winter homes in Mexico and California.
The drop in numbers of this beloved butterfly is partly because of farming practices in the U．S. Midwest, where monarchs are first born. Many farmers there use herbicides, or chemicals that destroy unwanted plants. Unfortunately, the herbicides are also destroying the milkweed plant, which monarch caterpillars (幼虫) feed on.
In the past 20 years, monarch butterflies have lost about 165 million acres of their habitats — an area about the size of Texas. That’s about a third of their summer breeding grounds (繁殖地). And most of their wintering grounds in Mexico and California have suffered from droughts, heat waves, and severe storms, which have been damaging to the creatures. Heavy logging (伐木) in these regions has also been destroying monarch habitats.
If officials label monarchs endangered, the U．S. Fish and Wildlife Service will try their best to ensure that monarchs do not die out.
“To protect our nation’s wildlife, the government should recognize the dangerous situation of monarchs，” says Sarina Jepsen of the Xerces Society. “Protection as an endangered species will enable monarch habitat recovery on both public and private lands.”
语篇解读：本文是一篇说明文。为拯救危难之中的北美帝王蝶，一些组织请愿将帝王蝶列为濒危物种，美国相关部门正在对此进行审议。
21．The purpose of the petition is probably to ask the U．S. government to ________.
A．take measures to stop monarchs moving
B．provide new natural habitats for monarchs
C．add monarchs to the list of protected species
D．work out how many monarchs there are
解析：选C 推理判断题。根据第二段的“it would take a year to decide whether the butterflies should be considered an endangered or a threatened species”以及“By officially labeling monarchs as endangered”可知，由于北美帝王蝶数量的骤减，一些组织向美国政府请愿，请求把帝王蝶纳入到濒危物种名单中，从而使政府制定计划来使帝王蝶的数量回升。
22．Each fall, monarch butterflies ________.
A．change their color from orange to black
B．need a lot of milkweed to feed themselves
C．die in large numbers because of the weather
D．travel long distances to look for warmer habitats
解析：选D 细节理解题。根据第三段的“known for their impressive, almost 3,000mile migration each fall”可知，帝王蝶每年秋天都会从北美洲飞行约3 000英里到墨西哥和加利福尼亚州过冬。
23．Paragraphs 4 and 5 mainly discuss ________.
A．the habitats monarchs prefer
B．the hard times monarchs are facing
C．the food monarch caterpillars feed on
D．the places where monarchs are first born
解析：选B 段落大意题。第四段和第五段主要分析了帝王蝶数量急剧下降的原因，即帝王蝶如今所面临的困境——除草剂的使用使得帝王蝶幼虫的食物遭到破坏；帝王蝶赖以生存的栖息地遭到严重破坏。
24．If officials label monarchs endangered, Sarina Jepsen will be very ________.
A．proud B．pleased
C．nervous D．surprised
解析：选B 推理判断题。Sarina Jepsen来自于向政府请愿的组织the Xerces Society，因此如果政府官员同意把帝王蝶纳入濒危物种名单中，他一定会很高兴。
