Question

Flying over a desert area in an airplane, two scientists looked down with trained eyes at trees and bushes. After an hour’s flight one of the scientists wrote in his book, “Look here for probable metal. ” Scientists in another airplane, flying over a mountain area, sent a message to other scientists on the ground, “Gold possible. ” Walking across hilly ground, four scientists reported, “This ground should be searched for metal. ” From an airplane over a hilly wasteland a scientist sent back by radio one word, “Uranium. ”

None of the scientists had X-ray eyes:  They had no magic power of looking down below the earth’s surface. They were merely putting to use one of the newest methods of locating minerals in the ground. . . trees and plants as signs that certain minerals may lie beneath the ground on which the trees and plants are growing.

This newest method of searching for minerals is based on the fact that minerals deep in the earth may affect the kind of bushes and trees that grow in the surface.

At Watson Bar Greek, a brook(小溪) six thousand feet high in the mountains of British Columbia, Canada, a mineral search group gathered bags of tree seeds. Boxes were filled with small branches from the trees. Roots were dug out and put into boxes. Each bag and box was carefully marked. In a scientific laboratory the parts of the forest trees were burned to ashes and tested. Each small part was examined to learn whether there were minerals in it.

Study of the roots, branches, and seeds showed no silver. But there were small amounts of gold in the roots and a little less gold in the branches and seeds. The seeds growing nearest to the tree trunks had more gold than those growing on the ends of the branches.

71. Scientists were flying over a desert or a hilly wasteland or a mountain area in order to search for_______in the ground.

A. gold                                              B. silver

C. metals                                           D. minerals

72. The scientists were searching for minerals by using_______ .

A. X-ray                                            B. magic power

C. a special instrument                 D. trained eyes

73. Which of the following is NOT mentioned as part of a tree that can help find minerals?

A. Leaves.                                        B. Roots.

C. Branches.                                      D. Seeds.

74. The study of trees, branches and roots shows that_______ .

A. there were larger amounts of gold in the branches than in the seeds

B. there were smaller amounts of gold in the roots than in the branches

C. there were less amounts of gold in the seeds growing on the ends of branches than seeds growing nearest to the tree trunks

D. there was more gold in the branches than in the roots

75. Which is the best title suggested below?

A. Scientists Searching for Metals with Special Power

B. New Methods of Searching for Minerals

C. Gold Could Be Found by Trees and Plants

D. A New Method of Searching for Minerals—Using Trees and Plants

Answer 1

71.【解析】选D。细节理解题。根据文章第一段的内容以及一般常识可推知答案。

72.【解析】选D。细节理解题。从文章第一段的第一句和第二段可找到答案。

73. 【解析】选A。细节理解题。从最后一段可知通过研究 roots, branches 和 seeds 可判定地下是否有矿产，而 leaves 在文章中却没有提到。

74.【解析】选C。细节理解题。从文中最后一句The seeds growing nearest to the tree trunks had more gold than those growing on the ends of the branches 可知。

75.【解析】选D。主旨大意题。通读全文可知答案为D。