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问题 填空题

空气、水是人类赖以生存的宝贵的自然资源．人类片刻也离不开空气．是因为空气中的氧气能______；将自来水变成纯水的操作是______；如果地下水硬度大．或者坑水中病原微生物过多．都可以采取的方法是______；鉴别地下水与蒸馏水一般在水样中加入______．

答案

人类片刻也离不开空气，氧气能支持燃烧和供给呼吸；将自来水变成纯水的操作是蒸馏；区分硬水和软水的方法是：用肥皂水，加入肥皂水，泡沫多的是软水，泡沫少的是硬水；降低水的硬度的方法是：加热煮沸、蒸馏，

故答案为：供给呼吸；蒸馏；加热煮沸；肥皂水．

多项选择题

下列项目中，可以计入存货成本的有______

A．商业折扣

B．购买材料的包装费

C．一般纳税人企业购入货物支付的增值税

D．进口货物关税

E．运输途中的合理损耗
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单项选择题

Like all the huge metropolises of the world, there are lots of diversions both outdoors and indoors in Chicago. The Art Institute of Chicago has one of the world’s (1) art collections, including more French Impressionist paintings than even in the Paris Louvre itself. The Field Museum of Natural History and the Museum of Science and Industry are also great historical and cultural treasure houses to (2) as well as entertain children and adults (3) In the Field Museum one comes (4) a surprisingly big collection of Chinese exhibits from the ancient (5) to the early century. The Sears Tower and the Buckingham Fountain are the pride of the Chicagoans; (6) having 110 storeys is said to be the highest tower in the world and the (7) is the largest fountain in the United States. Lake Michigan is for yachting in summer time, (8) the highlights of Chicago life all the year round are concerts, operas and plays (9) by the city’s orchestra, opera houses and theatres. In summer, especially around the Independence Day, July 4th, many festivals and fairs are given outdoors, which, (10) crowds and crowds of people, with their parades, fireworks, (11) concerts, water-skiing and good foods.

But with all its attractions and beautiful spots Chicago is also a city (12) for crimes. All the dwelling houses are (13) with three doors and visitors have to speak through microphone (14) in the wall to the residents before they can get admitted. In the streets there are white-color telephones. When one finds oneself (15) , he needs only to knock the receiver (16) the hook and the next instant the police will (17) . If one does not drive a car, it may well be dangerous for him or her to go out alone in the evening. At first I did not take this warning seriously. (18) , my two encounters with the Black people (19) dusk in the neighborhood were so unpleasant and frightening that I have (20) shut myself evenings in my room, in almost all studying, imposing a curfew on myself.

17（）

A. rescue him

B. come to his rescue

C. come to save

D.save
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