20．D　 查找信息题。从第三段第二句和第四段最后一句得出。

第十组

A

Can trees talk? Yes — but not in words. Scientists have reason to believe that trees do

communicate with each other. Not long ago, researchers learned some surprising things. First a willow tree attacked in the woods by caterpillars(毛毛虫)changed the chemistry of its leaves and made them taste so terrible that they got tired of the leaves and stopped eating them. Then even more astonishing, the tree sent out a special vapor—a signal causing its neighbors to change the chemistry of their own leaves and make them less tasty.

　 Communication, of course, does not need to be in words. We can talk each other by smiling, raising our shoulders and moving our hands. We know that birds and animals use a whole vocabulary of songs, sounds, and movements. Bees dance their signals, flying in certain patterns that tell other bees where to find nectar for honey. So why shouldn’t trees have ways of sending messages?

19．C　 查找信息题。从文中第三段第二句得出。

18．B　 推理判断题。从文中第二段最后一句推出，注意转折意义的unfortunately一词。

17．D　 查找信息题。从文中第一段第三句查找，so that…引出目的状语从句。

20．When do the birds return from South Africa to England every year?

A．summer　　　　 B．spring　　　　 C．winter　　　　 D．Both A and B

[解题导语]燕子有超凡的识途本领: 将其带到400英里以外的地方放飞，它们又飞回来了；它们迁徙到6，000英里的地方又能飞回到原来的家。

[答案与解析]

19．Swallows like to spend ”our winter” in　　 　　.

A．England　　　 B．London　　　　 C．Africa　　　 D．Germany

18．Which of the following is true?　　　 .

A．Seientists have found why the animals can see their nests.

B．No one knows why the swallows can fly back to their familiar landmarks.

C．It’s very simple that the birds use sense of direction.

D．Many experiments have been made on how birds can fly their way home

17．The seven swallows were marked on some of their feathers because　　　 .

A．they would be taken away by plane

B．they would be free in London

C．Croydon was 400 miles away

D．they could easily be seen for the red colour

16．B　 细节理解题。从第一段倒数第三句得知。

E

　　　 The Migration of Birds

　 Here is a scientific experiment on the homing of birds, the fact of which are quite certain. A few years ago seven swallows were caught near their nests at Bremen in Germany. They were marked with a red dye on some of their white feathers, so that they could easily been seen. Then they were taken by plane to Croydon, near London. This is a distance of 400 miles.

　 Then the seven swallows were set free at Croydon. Five of them flew back to their nests at Bremen. How did the birds find their way on that long journey, which they had never made before? That is the great puzzle. It is no good saying that the swallows have a sense of direction. These are just words and explain nothing. We want to know exactly what senses the animals use to find their way, how they know in which direction to go until they can see familiar landmarks. Unfortunately practically no scientific experiments have yet been made on this question.

　 Perhaps migrating birds are the greatest mystery of all. Swallows leave England in August and September, and they fly to Africa, where they stay during our winter. The swallows return to England in the late summer for the south. A lot has been found about the journeys of migrating birds by marking the birds with aluminum rings put on one leg. An address and a number is put on the ring.

　 Swallows from England go as far as South Africa and as many as fourteen birds, marked with rings in England, have been caught again in South Africa. From England to South Africa is a journey of 6,000 miles. And the birds not only return from Africa to England next spring, but often they come back to the nests in the very same house where they nested the year before.

15．B　 细节理解题。从第三段第一句中得知。