阅读理解。
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 f
or metals. "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 powers 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, using 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 on the surface.
At Waston Bar Greek, a brook(小溪)six thousand feet high in the mountains of British Colunbia,
Canada, a mineral search group gathered bags of tree seeds. Boxes were filled with small branches
from the trees. Roots were dug 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
trunk had more gold than those growing on the ends of the branches.
1. Scientists were flying over a desert of a hilly wasteland or a mountain area in order to search for_________ in the ground.
A. gold
B. silver
C. metals
D. minerals
2. 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 trunk
D. there was more gold in the branches than in tile roots
3. 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
4. The scientists were searching for minerals by using_________.
A. X-ray.
B. magic power
C. a special instrument
D. trained eyes
