题目内容
B. are you
C. have you
D. did you
Have you ever heard an echo of your voice?
An echo is a reflected(反射)sound. Stand in a very large, empty hall with nothing on the walls. Then shout. The sounds you make will hit the walls and come back to you. The walls reflect the sounds. These reflected sounds are called “echoes”.
We can use reflected sound to make sound travel farther. Hold a watch about fifty centimeters from your ear. You cannot hear it. The sound of the watch travels a short way in all directions. It does not travel as far as your ear. You can make it travel to your ear by using a roll of cardboard(纸板筒).
Make the roll of cardboard about fifty centimeters long. Put one end over your ear and hold the watch at the other. Now you can hear the watch because the sound has not gone in all directions. It is reflected down the roll to your ear.
A megaphone(喇叭筒)works in the same way. It makes sound travel farther. It reflects the sound into a beam which can travel a long way. In the ship, the sailor uses the megaphone to make his voice travel. Without the megaphone, his voice cannot travel far.
We use reflected sound in many ways. We use it to measure the depth of the sea, for example. Among the animals, bats and whales use reflected sound to tell them where they are and what things are near them.
【小题1】 Which is the right order of hearing our echo in a very large, empty hall?
a. We hear the reflected sound b. The sound returns to us
c. The sound hits the walls d. We make a sound
A.c, b, a, d | B.c, a, b, d | C.d, c, b, a | D.d, b, c, a |
A.reflected sound is useful only to blind people |
B.people haven’t made use of reflected sound yet |
C.bats use reflected sound to fly and get food |
D.whales don’t use reflected sound as they live in the sea |
A.a long piece of wood | B.a roll of cardboard |
C.a thin thread | D.a long piece of silk |
请仔细阅读下题五位人员的个人情况说明,从A-F中选出能解决他们问题的恰当建议。(有1个多余选项)(共5小题,计5分)
I. Students’ problems 1. My mother is a doctor. She is too busy with her work to spend the weekends with me. It seems that she doesn’t care me at all. I feel lonely. 2.. I am too shy to speak in front of my classmates. They always laugh loudly when I am answering teachers’ questions. 3.I am not allowed to meet friends at all. My parents want me to study all the time at home. I feel unhappy. 4.I think I work harder than others but I get bad grades. Am I too stupid? 5.A senior high school student asked me to give him ¥100 every week without telling others. I am frightened, so I don’t want to go to school now. |
II. Some good advice A. Nobody was born stupid. Maybe you haven’t got right ways of study yet. Ask the teachers or classmates for help if you have any questions. B. Your classmates may not laugh at you. If you don’t like their laugher, you should talk to them about your feelings. They might understand you. And you had better be more easygoing and be their friend. C. If you feel unhappy, go to have a good sleep and you will forget everything unhappy. D. Don’t be afraid. You should tell your parents or teachers at once. Don’t go out alone then. E. Let your parents know your friends are nice. You learn a lot from them as well as have fun with them. You study with them outside, too. F.Tell your mother you need her company sometimes. Also you should do some housework with your mother so she can finish her work quickly. Try to understand her, too. |