题目内容

【题目】在山羊遗传实验中,一黑色山羊与白色山羊杂交（白色与黑色由两对遗传因子控制且独立遗传）,子一代均为黑色。子一代个体间随机交配产生子二代个体中黑色∶浅黄色∶白色=12∶3∶1,则黑色个体和浅黄色个体中杂合子的比例分别为 （ ）

A．1/6、2/3 B．1/8、1/3

C．5/6、2/3 D．5/8、2/3

【答案】C

【解析】若用A和a、B和b表示相关的两对等位基因,由题意“子二代中黑色∶浅黄色∶白色=12∶3∶1”可推知,黑色为（9A B +3A bb或3aaB ）,浅黄色为（3aaB 或3A bb）,白色为aabb;在黑色个体中,纯合子有（1AABB+1AAbb或1aaBB）,其余都是杂合子,即杂合子占10/12=5/6;在浅黄色个体中,纯合子为（1aaBB或1AAbb）,其余为杂合子,即杂合子占2/3。

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In the past, man did not have to think about the protection of his environment. There were few people on the earth, and natural resources seemed to be __1__.

Today things are __2__. The world has become too __3__. We are using up our natural resources too quickly, and at the same time we are __4__ our environment with dangerous chemicals. If we continue to do this, human life on the earth __5__ not survive (生存).

Everyone __6__ today that if too many fish are taken from the sea, there will soon be none left. Yet, with modern fishing __7__, more and more fish are caught. We know that if too many trees are cut down, __8__ will disappear and nothing will grow on the land. Yet, we __9__ to use bigger and more powerful machines to __10__ more and more trees.

We realize that if rivers are polluted with waste products from factories, we will die. __11__, in most countries wastes are __12__ put into rivers or into the sea, and there are __13__ laws to stop this.

We know, too, that if the __14__ of the world continues to rise at the present rate, in a few years there will not be enough __15__. What can we do to solve these problems?

If we eat more vegetables and less __16__, there will be more food available for everyone. Land that is used to grow crops __17__ five times more people than land where animals are kept.

Our natural resources will __18__ longer if we learn to recycle them. The world population will not rise so quickly if people use modern methods of birth __19__.

Finally, if we educate people to think about the problems, we shall have a better and clearer __20__ in the future.

【1】A. beautiful B. unlimited C. rare D. valuable

【2】A. common B. same C. changeable D. different

【3】 A. crowded B. small C. dirty D. busy

【4】 A. protecting B. saving C. polluting D. fighting

【5】 A. may B. will C. shall D. could

【6】 A. wonders B. realizes C. considers D. discovers

【7】 A. poles B. boats C. methods D. ideas

【8】A. mountains B. seas C. trees D. forests

【9】 A. continue B. have C. start D. go

【10】 A. give up B. go out C. come own D. cut down

【11】 A. Thus B. However C. Generally D. Therefore

【12】A. still B. even C. also D. certainly

【13】A. too many B. a few C. some D. few

【14】A. production B. pollution C. population D. revolution

【15】 A. houses B. vegetables C. food D. lives

【16】 A. fruit B. meat C. fish D. grain

【17】 A. feeds B. increases C. supplies D. helps

【18】A. use B. stay C. keep D. last

【19】A. control B. protection C. plan D. reward

【20】A. nature B. sea C. planet D. forest

【题目】I don't think the charge for overhauling （大修）the equipment is excessive in _____ to its size.

A.correspondence

B.equation

C.proportion

D. dimension

【题目】某有机物A分子式为CxHyOz,15 g A完全燃烧生成22 g CO2和9 g H2O。

(1)该有机物的最简式是____________。

(2)若A是一种无色具有强烈刺激性气味的气体，具有还原性，则其结构简式是__________。

(3)若A和Na2CO3混合有气体放出，和醇能发生酯化反应，则A的结构简式为______________。

(4)若A是易挥发有水果香味的液体，能发生水解反应，则其结构简式为____________。

(5)若其分子结构中含有6个碳原子，具有多元醇和醛的性质，则其结构简式为____________。

【题目】有三种物质AC2、B2C2、AD4,元素A的最高正价和负价绝对值相等;元素B的单质能在C的气态单质中剧烈燃烧,火焰呈黄色,并生成淡黄色固体B2C2;元素D的负一价阴离子的电子层结构与氩原子的相同,则:

(1)A、B、C、D的元素名称分别为 、 、 、 。

(2)AD4分子中含有的共价键类型为 (填“σ键”或“π键”)。

(3)D的负一价阴离子的电子排布式为 ,B2C2的电子式为 ,属 (填“离子化合物”或“共价化合物”)。

【题目】Where are the woman’s keys?

A. In her pocket. B. On the floor. C. On the table.

【题目】B

The BBC was founded in 1922, including radio and television services. It is based at Broadcasting House in London.

The BBC is controlled by some governors chosen by the government, but these people have freedom and the government can’t interfere(干扰). That is, the BBC is supposed not to be the mouthpiece(代言人)of the government. It has to be as fair as possible in giving radio and television time to, for example, political parties and religious groups.

There is a kind of interesting service in Britishrental services. Many people prefer to rent their television sets instead of buying them.

The rent for a black and white set is about 80 pence a week. The rent of a color set is more than twice that of a black and white set. If the sets go wrong, people can have them repaired free of charge or replaced immediately.

Everyone has to buy a yearly license, since there is no advertising on BBC radio or television. It is from the sale of licenses that the BBC gets most of its money. A license for a black and white set costs 8 pounds, and for a color set 18 pounds a year.

There are four special radio channels, which broadcast different kinds of programmes. Radio 1 is mainly pop music. Radio 2 deals with light music, sports and other programmes. Radio 3 broadcasts serious music, talks on serious subjects, etc. News broadcasts are mainly given by Radio 4.

There are special programmes for Northern Ireland, Scotland, Wales, and certain parts of England. also broadcasts programmes about Britain — in many different languages as well as in English to all parts of the world.

【1】The officials in charge of the BBC ____________.

A. must say what the government wants to say

B. should give more time to political parties than to religious groups

C. are elected by the citizens from all over the country

D. can decide things without the permission of the government

【2】 If one wants to watch TV at home, everyone ____________.

A. has to buy a television set of his own

B. must rent a TV set

C. has to buy a license once a year

D. can change his damaged TV set for a new one without payment

【3】How does BBC get most of its money?

A. It gets money from all kinds of advertisements.

B. The BBC depends on the rent of TV sets.

C. The BBC gets money mainly by selling licenses and TV sets.

D. It gets its money mainly by selling licenses.

【题目】Recently I was frustrated that my essay was rejected by a newspaper．________, I had my wallet picked on the bus on the way home．

A．To be honest

B．To make matters worse

C．To tell you the truth

D．Believe it or not

【题目】Where does the conversation probably take place?

A. At a hospital.

B. At a restaurant.

C. At a handicraft shop.

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