Single mums are better at raising their kids than two parents 一 at least in the bird world. Mother zebra finches ¹ have to work harder and raise fewer chicks on their own，but they also produce more attractive sons who are more likely to get a mate.

    The finding shows that family conflict is as important an evolutionary driving force as ecological factors 2 such as hunting and food supply. With two parents around, there"s always a conflict of interests 3，which can have a detrimental effect on the quality of the offspring.

    In evolutionary terms 4，the best strategy for any parent in the animal world is to find someone else to care for their offspring，so they can concentrate on breeding again. So it"s normal for parents to try to pass the buck 5 to each other. But Ian Hartley from the UniversityofLancasterand his team wondered how families solve this conflict, and how the conflict itself affects the offspring.

    To find oiit 6，they measured how much effort zebra finch parents put into raising their babies. They compared single females with pairs, by monitoring the amount of food each parent collected, and removing or adding chicks so that each pair of birds was raising four chicks，and each single mum had two — supposedly the same amount of work.

    But single mums, they found, put in about 25 per cent more effort than females rearing with their mate. To avoid being exploited, mothers with a partner hold back from working too hard if the father is being lazy, and it"s the chicks that pay the price. “The offspring suffer some of the cost of this conflict, ” says Hartley.

    The cost does not show in any obvious decrease in size or weight, but in how attractive they are to the opposite sex. When the chicks were mature, the researchers tested the ” fitness" of the male offspring by offering females their choice of partner. Those males reared by single mums were chosen more often than those from two-parent families.

    Sexual conflict has long been thought to affect the quality of care,given to offspring, says zoologist Rebecca Kilner atCambridgeUniversity, who works on conflict of parents in birds. ” But the experimental evidence is not great. The breakthrough here is showing it empirically. ”

    More surprising, says Kilner, is Hartley"s statement that conflict may be a strong influence on the evolution of behaviour, clutch size and even appearance. “People have not really made that link," says Hartley. A female"s reproductive strategy is usually thought to be affected by hunting and food supply. Kilner says conflict of parents should now be taken into account as well.

词汇：

evolutionary /,i: və"lu:ʃənəri/adj．进化的

detrimental /detrimentəl/adj．有害的

offspring /"ɔfspriŋ/n．（单复数同形）儿女，子孙，后代

empirically /em"pirikli/adv．以经验为根据地

ecological /i:kə"lɔdʒikəl/adj．生态的

reproductive /,ri:prədʌktiv/adj．生殖的

experimental /eks,peri"mentəl/adj．实验的，根据实验的

clutch /klʌtʃ/ n．一次产的或孵的卵

注释：

1.zebra finch：斑胸草雀，一种澳大利亚小鸟，它有黑白色条纹，而且是受欢迎的笼养鸟。

2.family conflict is as important an evolutionary driving force as ecological factors：家庭冲突是与生态因素同样重要的进化推动力。

3.a conflict of interests：利益冲突

4.in evolutionary terms：从进化的角度讲。in... terms, in terms of...：从……方面来讲，就……而言。例如：It has been a terrible year in terms. of business．就生意而论，这是很糟糕的一年。

5.pass the buck (to)：推卸责任，把为难的事推给别人。例如：Bus companies are just passing the buck by saying their drivers are responsible for delays．公交公司说司机应该对误点的事负责，这只是在推卸责任。

6.find out：这是一个承上的短语，从逻辑上讲，它的宾语应该是：how families solve this conflict, and how the conflict itself affects the offspring.  

According to the passage, in what way does family conflict affect the quality of the offspring?

A:The young males get less care B:The young females will decrease in weight C:The offspring will become lazy fathers or mothers in the future D:The offspring will not get mature easily

Of all the areas of learning the most important is the development of attitudes: emotional reactions as well as logical thought processes affect the behavior of most people. "The burnt child fears the fire" is one instance; another is the rise of despots like Hitler. Both these examples also point up the fact that attitudes come from experience. In the one case the experience was direct and impressive; in the other it was indirect and cumulative. The Nazis were influenced largely by the speeches they heard and the books they read.
The classroom teacher in the elementary school is in a strategic position to influence attitudes. This is true partly because children acquire attitudes from those adults whose words are highly regarded by them.
Another reason it is true is that pupils often devote their time to a subject in school that has only been touched upon at home or has possibly never occurred to them before. To a child who had previously acquired little knowledge of Mexico his teacher’s method of handling such a unit would greatly affect his attitude toward Mexicans.
The media through which the teacher can develop wholesome attitudes are innumerable. Social studies (with special reference to races, creeds and nationalities), science matters of health and safety, the very atmosphere of the classroom... these are a few of the fertile fields for the inculcation of proper emotional reactions.
However, when children go to school with undesirable attitudes, it is unwise for the teacher to attempt to change their feelings by cajoling or scolding them. She can achieve the proper effect by helping them obtain constructive experiences.
To illustrate, first-grade pupils afraid of policemen will probably alter their attitudes after a classroom chat with the neighborhood officer in which he explains how he protects them. In the same way, a class of older children can develop attitudes through discussion, research, outside reading and all-day trips.
Finally, a teacher must constantly evaluate her own attitudes, because her influence can be negative if she has personal prejudices. This is especially true in respect to controversial issues and questions on which children should be encouraged to reach their own decision as a result of objective analysis of all the facts. (377 words)
Notes: point up (= emphasize) 强调，突出。touch upon 触及。creed 信条，教义。inculcation 谆谆教诲。cajoling 哄骗。
The central idea conveyed in the above text is that

A:attitudes affect our actions. B:teachers play a significant role in developing or reshaping pupils’ attitudes. C:attitudes can be modified by some classroom experiences. D:by their attitudes, teachers don’t affect pupils’ attitudes deliberately.

Of all the areas of learning the most important is the development of attitudes.. emotional reactions as well as logical thought processes affect the behavior of most people. "The burnt child fears the fire" is one instance; another is the rise of despots like Hitler. Both these examples also point up the fact that attitudes come from experience. In the one case the experience was direct and impressive; in the other it was indirect and cumulative. The Nazis were influenced largely by the speeches they heard and the books they read.
The classroom teacher in the elementary school is in a strategic position to influence attitudes. This is true partly because children acquire attitudes from those adults whose words are highly regarded by them.
Another reason it is true is that pupils often devote their time to a subject in school that has only been touched upon at home or has possibly never occurred to them before. To a child who had previously acquired little knowledge of Mexico his teacher’s method of handling such a unit would greatly affect his attitude toward Mexicans.
The media through which the teacher can develop wholesome attitudes are innumerable. Social studies (with special reference to races, creeds and nationalities), science matters of health and safety, the very atmosphere of the classroom... these are a few of the fertile fields for the inculcation of proper emotional reactions.
However, when children go to school with undesirable attitudes, it is unwise for the teacher to attempt to change their feelings by cajoling or scolding them. She can achieve the proper effect by helping them obtain constructive experiences.
To illustrate, first-grade pupils afraid of policemen will probably alter their attitudes after a classroom chat with the neighborhood officer in which he explains how he protects them. In the same way, a class of older children can develop attitudes through discussion, research, outside reading and all-day trips.
Finally, a teacher must constantly evaluate her own attitudes, because her influence can be negative if she has personal prejudices. This is especially true in respect to controversial issues and questions on which children should be encouraged to reach their own decision as a result of objective analysis of all the facts.
The central idea conveyed in the above text is that

A:attitudes affect our actions. B:teachers play a significant role in developing or reshaping pupils’ attitudes. C:attitudes can be modified by some classroom experiences. D:by their attitudes, teachers don’t affect pupils’ attitudes deliberately.

The computer will soon affect ______.

A:people in large cities B:people in developed countries C:all humanity D:the Western world

阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。

A:effect B:affect C:effected D:affected

Chimpanzee extinction may affect（）

A:healthier lifestyle B:some human disease treatments C:some diseases D:human survival E:human genomes key areas

Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells (1) when to form flowers and when the flowers should open. It tells (2) when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal (3) the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur (4) the number of hours of daylight. In the short (5) of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer.
Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration (6) twice each year. Birds (7) flying become restless when it is time for the trip, (8) they become calm again when the time of the flight has ended.
Scientists say they are beginning to learn which (9) of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain (10) to control the timing of some of our actions. These (11) tell a person when to (12) , when to sleep and when to seek food. Scientists say there probably are other biological clock cells that control other body activities.
Dr. Moorhead is studying (13) our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours.
(14) can take many days for a human body to accept the major change in work hours. Dr. Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said (15) understanding could cut sickness and accidents at work and would help increase a factory’s production.

A:effect B:affect C:effected D:affected

More about Alzheimer’s Disease 　　Scientists have developed skin tests that may be used in the future to identify people with Alzheimer’s disease1 and may ultimately allow physicians to predict ________ (51) is at risk of getting this neurological disorder. 　　The only current means of ________ (52) the disease in a living patient is a long and expensive series of tests that eliminate every other cause of dementia.(痴呆) 　　“ Since Alois Alzheimer described the ________ (53) nearly a century ago，people have been trying to find a way to ________ (54) diagnose it in its early stages2，” said Patricia Grady，acting director3 of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. "This discovery, if ________ (55) , could prove a big step forward in our efforts to deal with and understand the disease. ” 　　Alzheimer’s is the single greatest ________ (56) of mental deterioration in older people, affecting between 2. 5 million and 4 million people in the United States ________ (57). The devastating disorder gradually destroys memory and the ability to function，and eventually causes death.6 There is currently no known _______ (58) for the disease. 　　Researches ________ (59) that the skin cells of Alzheimer’ s patients have defects that interfere with their ability to regulate the flow of potassium in and out of the cells. The fact that the cell defects are present in the skin suggests that7 Alzheimer’s ________ (60) from physiological changes throughout the body，and that dementia may be the first noticeable effect of these changes as the defects ________ (61) the cells in the brain, scientists said. 　　The flow of potassium is especially ________ (62) in cells responsible ________ (63) memory formation8. The scientists also found two other defects that affect the cells’ supply of calcium, another critical element. 　　One test developed by researches calls for9 growing skin cells in a laboratory culture and then testing them with an electrical detector to determine if the microscopic tunnels that ________ (64) the flow of potassium are open. Open potassium channels create a unique electrical signature. 　　A spokesman for the Alzheimer’s Association said that if the validity of the diagnostic test can be proven it would be an important ________ (65) , but cautioned that other promising tests for Alzheimer’s have been disappointing.

A:affect B:remove C:collect D:form