電大工商學位英語考試--閱讀理解練習1

[@more@]

Monarch butterflies（黑脈金斑蝶）are a common summer sight in the northern United States and Canada . These large orange and black insects（昆蟲）brighten parks and gardens as they fly lightly among the flowers . What makes monarchs particularly interesting is that they migrate（遷飛）—all the way to California or Mexico and back . They are thought to be the only insect that does this .

Every year in the late summer monarchs begin their journey to the south . Those heading for Mexico go first for the Louisiana-Mississippi area , then fly across the Gulf of Mexico into Texas . Once in Mexico , they settle themselves in one of about fifteen places in a mountain forest filled with fir trees . Each place provides a winter home for millions of monarchs . The butterflies are so many that they often cover entire trees . When spring comes , they begin their long journey north .

The question is often asked whether every butterfly makes the round-trip journey every year . And the answer is no . The average monarch lives about nine months . So one flying north might lay eggs in Louisiana and then die . The eggs of that generation may be found in Kentucky ; the eggs of the next generation may end up in Wisconsin or Michigan . The last generation of the season , about the fourth , will make their way back to Mexico and restart the journey .

Scientists learn about monarchs’ migration by catching and making marks on the insects . By recatching a monarch with such a mark and noticing where it came from , the next scientist can get to know things like the butterfly’s age and its routing（路線）.

1. One of the places where monarchs spend the winter is ________.

A. the Gulf of Mexico B. an area in Mississippi

C. a forest in Mexico D. a plain in Texas

2. The routing of monarchs’ migration can be learned ________.

A. by examining the marks made on them

B. by collecting their eggs in the mountains

C. by comparing their different ages

D. by counting the dead ones in the forests

3. What is the subject discussed in the passage ?

A. Migration of monarchs . B. Scientists’ interest in monarchs .

C. Winter home of monarchs . D. Life and death of monarchs .

答案：1. C 2. A 3. A

在北美和加拿大地區，黑脈金斑蝶在夏季十分常見。當這些明橙色和黑色相間的大昆蟲在花朵間翩翩起舞的時候，使得公園和花壇都變得活躍起來。有趣的是黑脈金斑蝶的遷飛--總是往返於加利福尼亞或墨西哥。人們認為，只有這種昆蟲才這樣做。

每年的夏末黑脈金斑蝶開始它們向南遷飛。目標方向墨西哥，首先進入路易斯安那-密西西比河地區，然後它們穿過墨西哥灣進入得克薩斯。一旦進入墨西哥，它們便會在大約十五分之一的冷杉樹林密集的大森林內安頓下來。每一片冷杉樹林密集的地方會為成千上萬的黑脈金斑蝶提供越冬的場所。蝴蝶數量多的時候，它們經常會遍佈整片樹林。當春季來臨的時候，它們又開始向北遷飛。

經常有人問是否每隻蝴蝶每年都這樣反覆的遷飛於兩地。答案是不。黑脈金斑蝶的平均壽命是9個月。所以蝴蝶向北遷飛，有可能在路易斯安那產卵後便死掉了，也有可能在肯塔基州產卵；也有可能在威斯康星或密歇根州產卵。最後的繁殖季節，大概是第四次繁殖，它們將返回墨西哥開始新一程的遷飛。

科學家們為了研究黑脈金斑蝶的遷飛習性，通常將捕捉到的蝴蝶做上記號，然後透過捕捉這些標有記號的黑脈金斑蝶，來觀察蝴蝶飛來的方向，科學家以此方法來對黑脈金斑蝶進行研究，如它們的年齡和飛行路線等。