问题 填空题

发生地震、洪涝灾害地区的灾民用以下几个步骤可将河水转化为饮用水,其处理过程为①加入明矾  ②加入消毒剂  ③静置沉淀  ④加热煮沸   ⑤活性炭吸附  ⑥过滤.

(1)其合理的顺序是(填序号)______.

(2)向河水中加入明矾的作用是______;过滤可以除去水中______的杂质;向水中加入活性炭,其作用是______.

(3)为了判断得到的水是硬水或软水,可加入______进行检验.用硬水洗衣服,不容易洗干净.为使衣服能洗干净,你给他们提出的一条建议是______.

答案

(1)水的净化过程一般是用明矾然后过滤来除去先除去水中的不溶物,再用活性炭除去水中的异味等,最后杀菌消毒,然后煮沸即可饮用.所以,其合理的顺序是:①③⑥⑤②④;

(2)由于明矾加入水形成的胶状物对杂质的吸附,所以,向河水中加入明矾的作用是吸附悬浮杂质使之沉淀;过滤可以除去水中难溶性固体的杂质;由于活性炭有吸附性,向水中加入活性炭,其作用是吸附色素和异味;

(3)为了判断得到的水是硬水或软水,可加入肥皂水进行检验.用硬水洗衣服,不容易洗干净.由于生活中将硬水软化常用的措施是:煮沸.所以,为使衣服能洗干净,给他们提出的一条建议是煮沸后用.

故答为:(1)①③⑥⑤②④;(2)吸附悬浮杂质使之沉淀,难溶性固体,吸附色素和异味;(3)肥皂水,煮沸后用.

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Part 4


Questions 26-45


·Read the following passage and decide which answer bestfits each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.
The "standard of living" of any country means the (26) person’s share of the goods and services which the country produces. A country’s standard of living, therefore depends (27) and foremost on its capacity to produce wealth. "Wealth" in this (28) is not money, for we do not live on money (29) on things that money can buy: "goods" such as food and clothing, and "services" such as (30) and "entertainment".
A country’s capacity to produce wealth depends upon many factors, most of which have an effect (31) one another. Wealth depends (32) a great extent upon a country’s natural resources. Some regions of the world are well supplied with coal and minerals, and have a (33) soil and a favorable climate; other regions (34) none of them.
Next to natural resources (35) the ability to turn them to use. China is perhaps as well off as the USA in natural resources, but suffered for many years from (36) and external wars, and for this and other reasons was incapable (37) her resources. Sound and (38) political conditions, and freedom from foreign invasion, enable a country to develop its natural resources peacefully and steadily, and to produce more wealth than another country (39) well served by nature but less well ordered.
A country’s standard of living does not only depend upon the wealth that is produced and (40) within its own borders, but also upon what is indirectly produced through international trade. For example, Britain’s wealth in foodstuffs and other agricultural products would be much (41) if she had to depend only on those grown at home. Trade makes it possible for her surplus manufactured goods to be traded abroad for the agricultural products that would (42) be lacking. A country’s wealth is, therefore, much (43) by its manufacturing capacity, (44) that other countries can be found ready to (45) its manufactures.

A.way

B.feeling

C.sense

D.occasion