《2025年节节高大象出版社八年级英语上册仁爱版》

D
Astronomers are scientists who study the stars and planets. Before any visitors reached the moon,astronomers described it,as a silent place. 36.B_ Then astronauts landed on the moon and talked to one another as they did research on its surface. Were the astronomers wrong?
To find the answer,we must know something about sound waves (声波). Sound waves need medium (介质),such as water and air,to carry them along 37.C_ If there is no air,sound waves cannot travel. Imagine that you put a television in a large glass box without air. 38.E_ However,as there is nothing to carry the sound waves,you will hear no sound.
The surface of the moon has no air either. So the astronomers were right. The moon is silent. Then how could the astronauts talk to each other while they were there? 39.A_ The astronauts carried equipment (设备) to send and receive radio waves. Radio waves are different from sound waves. 40.D_ The astronauts can talk to each other by radio. But the moon itself is just as silent as ever.

根据材料内容,从下面五个选项中选出能填入文中空缺处的最佳选项,使文章意思通顺、内容完整。
A. Well,they went to the moon prepared.
B. They said that there could be no sounds at all.
C. On the earth,sounds travel through air to reach our ears.
D. They travel very fast and need nothing to carry them along.
E. You can see that the power is on and the volume (音量) is up.

答案： 36—40 BCEAD