题干

深冷分离法又称低温蒸馏法.该法能将空气中的氧气和氮气分离出来,深冷分离法原理:以空气为原料,经压缩等处理使空气成为液态空气(液空).再进入干燥净化器,除去其他成分,最后分离出氮气和氧气.

(1)物质的变化有物理变化和化学变化.深冷分离法属于____变化.

(2)空气经压缩等处理成液空的过程中发生的物态变化是____

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物理,液化

同类题2

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    With more and more cars on the road, traffic jams (堵车) are inevitable. Traffic jams can lead to more accidents as there are more cars, with more people trying to get to their destination, all the while getting worse. Although it's impossible to avoid traffic jams altogether, there are some tips you can follow to reduce the amount of time on the road.

    Check for traffic jams before you leave. You can listen to the radio for traffic news, or check on the Internet to get up-to-minute information on traffic. If the route you want to take is heavy with traffic, you can choose another.

    Look for a different route all the time. Most traffic jams happen on busy roads. Using country roads could avoid a lot of traffic. Although the distance you may have to travel is further, it can work out quicker.

    Set your car radio to receive traffic bulletins. Many new car stereo systems (汽车音响系统) are equipped with a radio system by which you can hear the traffic channel. This way you can get the latest traffic information and change your journey if necessary.

    __________. Most traffic jams usually occur(发生) during rush hour, so try to avoid this time period if possible. Some jobs offer flexible working hours so that you can travel to work outside of rush hour. Some jobs even allow you to work at home so as to avoid moving altogether. Ask your manager to see what you can do if traffic is a problem for you.

    Use public transport instead. The easiest way to avoid traffic jams is to take buses or the underground instead of driving your own car. Not only will you avoid traffic jams but you will most likely be saving money.

同类题4

任务型阅读

    Here's how yo-yo dieting affects your body and your mind

    Yo-yo dieting, also known as weight cycling, occurs when a person experiences periods of weight loss followed by weight gain followed by weight loss and so on and so on. The effects of this weight cycling are significant, even when the weight lost and gained is as little as 10 pounds.____

    It can make you gain weight

    While dieting may help you lose a few pounds at first, it only works temporarily. Your body responds to the lack of calories by turning to lean muscle mass for energy. Once you have returned to your normal eating habits, the weight comes back on –____

    ____

    Yo-yo dieting may increase the risk for heart disease and sudden death in post-menopausal(绝经后期)women. Studies found that when normal-weight women experienced periods of weight cycling, they were 3.5 times more likely to have sudden death than women whose weight remained stable. In the same study, yo-yo dieting increased a woman's risk of death by 66 percent.

It can be damaging to your skin

    Dermatologist (a doctor who studies and treats skin diseases) Robin Evans weighed in on the effect that yo-yo dieting has on the skin. “The up and down weight losses and gains can have harmful effects on the skin especially on the face with stretching and contracting the skin,” said Evans____.

It plays games with your mind

    Yo-yo dieting is hard on the body,____ Repeatedly gaining and losing weight can leave dieters feeling more depressed about their weight and losing self-belief as a result.

    If you're a yo-yo-dieter, talk to your health care provider about lifestyle changes that can help you maintain a stable and healthy weight for years to come.

A. It only works temporarily

B. It can damage your heart

C. but in the form of fat, not muscle

D. but it's even harder on the mind

E. but with a smaller size, you will make yourself less friendly

F. The result ends up more wrinkles and an overall effect of aging the skin

G. We turned to the experts to find out how yo-yo dieting can affect your body and your mind