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单选题 A dust explosion occurs when a large amount of dust mixed with air catches fire. Around paper mills, threshing machines, and com mines, enough dust gathers to make dust explosions a hazard, especially when there is a nearby source of heat. Most metals that do not ordinarily burn will catch fire when they are finely ground. Many substances that do not burn easily when in large pieces will explode quickly when in the form of ______
学科：22232工程学科英语
时间：2023-06-14 12:14:50
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题目1单选题
Low temperatures cause outdoor telephone lines to contract and become taut. High temperatures cause them to expand. In the summer, telephone lines often ______A. breakB. sweatC. humD. sag
题目2单选题
A dust explosion occurs when a large amount of dust mixed with air catches fire. Around paper mills, threshing machines, and com mines, enough dust gathers to make dust explosions a hazard, especially when there is a nearby source of heat. Most metals that do not ordinarily burn will catch fire when they are finely ground. Many substances that do not burn easily when in large pieces will explode quickly when in the form of ______A. coalB. dustC. metalsD. heat
题目3单选题
The fall line is the edge of a plateau region where several rivers descend from the upper level to a plain below. The waterfalls along this line are a source of hydroelectric power used to run machinery in factories, The availability of waterpower makes the fall line an advantageous location for ______A. waterfallsB. industrial citiesC. inland waterwaysD. vacation retreats
题目4单选题
The rates of expansion and contraction as a result of temperature changes are not the same for solids and for liquids. Consequently, degrees of temperature registered on a thermometer made of glass, containing a liquid, are slightly ______A. invariableB. readableC. exaggeratedD. inaccurate
题目5单选题
A ball can be moved more easily than a cube of the same material and volume at rest on the same surface. This is so partly because the ball has less of its area resting on the surface and therefore creates less friction to inhibit its movement. The same principle applies to the movement of dry sand on a seashore. The grains of a sand dune are generally spherical and hence the position of the dune ______A. disappearsB. shifts easilyC. never changesD. resists movements
题目6单选题
Nuclear physics has given us encouraging glimpses into infinitesimal structures of matter. Progress is being made in studying the mysteries of the living cell. Scientists are learning how to manipulate molecular particles to produce new drugs, materials, and plastics. The tremendous energy of the sun is being brought within our reach. There is scarcely a source of physical power that is not within the ultimate possibility of ______A. our imaginationB. our own destructionC. human controlD. space exploration
题目7单选题
The shorter a pendulum is, the faster it swings. Most pendulum clocks have a setscrew by which one may adjust the length of the pendulum when the clock is not keeping accurate time. If the clock is running too fast, the pendulum is swing too fast and it should be ______A. shortenedB. stoppedC. lengthenedD. replaced
题目8单选题
Power plants that generate electricity by means of atomic energy are in operation in several countries. Scientists hope to solve many of the problems in the use of atomic energy, and many scientists now believe that atomic energy will be the most important source of electric power ______A. in the futureB. when it is triedC. in the laboratoryD. in the army
题目9单选题
There are a number of nuclear power plants now built or under construction by the government and by investor-owned power companies. Although most of the electricity used in the world is generated in steam or hydroelectric power plants, nuclear plants will help to meet increasing demands for ______A. electrical appliancesB. safe investmentC. weapons researchD. electric power
题目10单选题
Since buildings with steel or ferroconcrete frames can move up and down as one body, they receive little damage from an earthquake. Similarly, the ancient Greeks built their comparatively light temples on massive platforms of masonry set on swampy ground. During an earthquake, the platform rocked as a whole, and the temple ______A. was damagedB. stayedC. sank in the swampD. was destroyed
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