题目内容
Temperature is measured by means of a thermometer (温度计). One general form of thermometer depends upon the fact that most solids and liquids expand as their temperature rises. There are one or two exceptions. There is, for instance, a kind of steel called invar (from “invariable”) which does not change its dimensions as temperature changes; it is valuable for making pendulums (钟摆), since, if the length of a pendulum changes, its time of vibration changes. It is also used for making very accurate measuring scales. In both cases, then, changes of atmospheric temperature have no effect if invar is used.
Another exception is that very odd liquid, water, which has many strange properties (特性). As water gets colder it contracts (收缩), which is ordinary behavior, until it reaches the temperature of 30℃. above freezing point. After that, as it gets colder, it expands. This is fortunate---for considering the freezing of a pond. As the water on top gets colder, it shrinks; and so, volume for volume, it becomes heavier and sinks. This goes on until all the pond is at 30℃, but after that, as the water becomes colder it expands. Therefore the colder water stays on top and freezes, covering the pond with ice. If the water went on contracting down to the freezing point, the pond would become a solid block of ice in the end. This would not worry people who live in hot climates, but it would be very serious for those who live in cold climates, especially for those who want to break the ice and catch fish which live in the cold water beneath.
1. Invar is valuable for making pendulums because _______.
A. it can hardly change its shape or size as temperature changes.
B. it will change its dimensions without the change of temperature.
C. its time of vibration doesn’t change if its length changes.
D. its time of vibration does not change if its length changes.
2. As water gets colder after reaching the temperature of 30℃. it will _______.
A. contract B. shrink C. expand D. freeze
3. Which of the following statements is true, according to this passage?
A. Only invar can be used to make a thermometer.
B. Only water can be used to make a thermometer.
C. Both invar and water can be used to make a thermometer.
D. Neither invar nor water can be used to make a thermometer.
4.The best title of this passage is most likely to be _____.
A. Temperature Measurement B. Two Exceptions
C. Uses of Invar D. Properties of Water
ACDB
【解析】略
王后雄学案教材完全解读系列答案
海淀课时新作业金榜卷系列答案When we look at the sky and see a bright light moving quickly across it or coming towards the earth, we talk about seeing a “shooting star” or a “falling star”. These moving lights are not, in fact, stars at all. They are small pieces of matter from outer space, which burn up as they enter the Earth’s atmosphere. The correct name of them is meteoroids. Any pieces that make it to the Earth’s surface without completely burning up are known as meteorites. A meteor is actually the name given to the light we see when a meteoroid is burning up.
When a meteorite hits the Earth at speeds between 11 and 72 kilometers a second, it can do amazing damage. A very large meteorite could knock the earth out of its orbit. If this happened, all life on Earth would probably become extinct（灭绝）. The path we follow around the Sun would change and as a result the Earth would become either much hotter or much colder. This change in temperature would affect sea levels and the amount of water in rivers. There would either be huge floods, which would cover most of the land with water, or the oceans would dry up and there would be a drought, which means a long period of time without rain. Either way, nothing could survive. If a large meteorite landed in the sea it would almost certainly cause tsunamis, which would race towards the land, destroying everything in their paths.
Although it is unlikely the Earth will be struck by a meteorite large enough to do that kind of damage, there is evidence of fairly large meteorites hitting the Earth in the past. In 1908 a large area of forest in Tunguska, Siberia was destroyed by a meteorite that came apart just before it hit the ground. The moon, however, has about three billion craters陨石坑caused by meteorites impacting影响 its surface. The reason more meteorites have reached the surface of the moon than the surface of the Earth is that the moon does not have enough atmosphere for the meteorites to burn up in. some of the meteorites that have reached the Earth’s surface have done considerable damage. Some scientists believe it was a change of climate caused by meteorites hitting the Earth that resulted in the extinction of the dinosaurs and other large prehistoric animals.
Scientists are especially interested in meteorites because they contain information about the solar system. It is widely believed by scientists that most meteorites are produced by collisions（碰撞） between asteroids (small planets). These collisions probably happened many billions of years ago. This means the physical and chemical structure of a meteorite can give scientists information about the early days of the universe.
1.The story is about ___.
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A．floods caused by meteors |
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B．matter from outer space |
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C．life on Earth millions of years ago |
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D．meteorites that have damaged the moon |
2.The Earth has ___.
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A．three billion craters |
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B．fewer craters than the moon |
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C．more craters than the moon |
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D．a thinner atmosphere than the moon |
3.Some scientists believe the dinosaurs became extinct because ___.
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A．they were hit by meteors |
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B．meteorites landed on their nests |
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C．meteorites landed and changed the climate |
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D．they could no longer breathe the atmosphere |
4.Meteors are ___.
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A．small planets |
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B．the same as asteroids |
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C．from broken parts of asteroids |
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D．the light we see when meteoroids hit our atmosphere |
17．---The weather repot says the temperature is going to drop sharply. Do remember to put on more clothes.
--- __________
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A．Made it |
B．Got it |
C．Understood it |
D．Heard it |