In species in which females are the homogametic sex, gender of offspring is determined by the male.

According to a new study. ______.

A．sex ratio is determined by where people live

B．sex ratio at birth is skewed all over the world

C．the skewed sex ratio is a natural phenomenon

D．the percentage of boys born varies with latitude

Earthquakes are the most lethal of all natural disasters. What causes them? Geologists explain them in terms of a theory known as plate tectonics. Continents are floating apart from each other, this is referred to as the continental drift. About sixty miles below the surface of the sea, there is a semimolten bed of rock over which plates, or slabs, carry continents and sea floors at a rate of several inches a year. As the plates separate from each other, a new sea floor is formed by the molten matter that was formerly beneath. Volcanic islands and large mountain ranges are created by this type of movement. The collision of plates causes geological instability such as that in California called the San Andreas Fault, located between the Pacific and North American plates. The plates there are constantly pushing and pulling adjacent plates, thereby creating constant tremors and a potential for earthquakes in the area.

Geologists would like to be able to predict earthquakes accurately. Using laser beams, seismographs, gravity-measuring devices, and radio telescopes, they are presently studying the San Andreas Fault to determine the rate of strain and the amount of ground slippage. Calculations indicate that sometime within the next ten years, California will be struck by a major earthquake.

In spite of the geologists' theory of plate tectonics, there are still gaps in man's understanding and knowledge of the causes of earthquakes. Powerful earthquakes have occurred in places where plate boundaries are hundreds of miles away. In the 1800s, New Madrid, Missouri and Charleston, South Carolina, were shaken by earthquakes that no one had foreseen.

Certain areas of the world are quake prone. Italy, Yugoslavia, and Algeria have experienced many quakes. In November 1980, Naples was struck by an especially devastating quake. China and Japan have also been hit by horrendous quakes. In 1923, Tokyo and Yokohama were reduced to rubble by gigantic tremors that were followed by fires, tornadoes, and finally a thirty-four-foot tsunami, or tidal wave, which was caused by the earth's drop into the waters of Tokyo Bay. More than 150,000 people died in that earthquake.

What effects have geologists' predictions of earthquakes had? The Chinese in Haicheng in 1974 were warned that an earthquake might occur within the next year or two. With the help of amateur seismologists' observations of animal behavior. and the rise and fall of water in wells and measurements of quantities of radioactive gas in water, professional geologists were able, in January 1975, to predict an earthquake within the next six months. On February 4, Haicheng was destroyed, but because its residents have been evacuated, very few people were killed. In California, where earthquake is an ever present menace, building codes now require quakeproof structures, and Civil Defense units have intensified their training in how to deal with disaster should it strike or, perhaps more accurately, when it strikes. Should predictions of a quake within the next ten years be accurate, many Californians may be able to save both their lives and their property.

Continental drift is the concept that ______.

A．continents are drawing nearer to each other

B．continents are separating

C．continents are 60 miles apart from each other

D．new continents are developing beneath the sea

Whom are the speakers expecting to come soon? 查看材料

A.A postman.

B.A salesman.

C.A repairman.

D.A policeman.

All of the following are the strategies employed by the famous firms to attract talents EXCEPT

A．promoting their image

B．improving the reputation of their products

C．taking advantage of advertisements and media

D．revealing the truth of the firms

All of the following are the strategies employed by the famous firms to attract talents EXCEPT ______ .

A．promoting their image

B．improving the reputation of their products

C．taking advantage of advertisements and media

D．revealing the truth of the firms

Sex prejudices are based on and justified by the ideology that biology is destiny. According to this ideology, basic biological and psychological differences exist between the sexes. These differences require each sex to play a separate role in social life. Women are the weaker sex both physically and emotionally. Thus, they are naturally suited, much more so than men, to the performance of domestic duties. A woman's place, under normal circumstances, is within the protective environment of the home. Nature has determined that women play caretaker roles, such as wife and mother and homemaker. On the other hand, men are best suited to go out into the competitive world of work and politics where serious responsibilities must be taken on. Men are to be the providers; women and children are "dependents."

The ideology also holds that women who wish to work outside the household should naturally fill those jobs that are in line with the special capabilities of their sex. It is thus appropriate for women, not men, to be employed as nurses, social workers, elementary school teachers, household helpers, and clerks and secretaries.

These positions are simply an extension of women's domestic role. Informal distinctions between "women's work" and "men's work" in the labor force, according to the ideology, are simply a functional reflection of the basic differences between the sexes.

Finally, the ideology suggests that nature has worked her will in another significant way. For the human species to survive over time, its members must regularly reproduce. Thus, women must, whether at home or in the labor force, make the most of their physical appearance.

So goes the ideology. It is, of course, not true that basic biological and psychological differences between the sexes require each to play sex-defined roles in social life. There is ample evidence that sex roles vary from society to society, and those role differences are largely learned.

But to the degree people actually believe that biology is destiny and that nature intended for men and women to make different contributions to society, sex-defined roles will be seen as totally acceptable.

Women's place, some people think, is within the protective environment of the home because______.

A．women can provide better care for the children

B．women are too weak to do any agricultural work at all

C．women are biologically suited to domestic jobs

D．women cannot compete with men in any field

Women earn less than men do. For example, in 1998 the hourly wages of women in the U. S. were 26% less than those of men. The gap between male and female incomes becomes wider with age. The gap between the labor incomes of young women and young men varies. It's also clear that jobs in which women are concentrated pay less. The larger the number of workers who are women in an industry, the lower the average wages.

Why do women earn less than men do? Are the differences explained by the fact that women are looked down upon? If so, the government has to intervene (干预) ,to force the employers to pay equal wages to equal jobs. However, there is no agreement among economists about the causes of the gap. One view argues that women on the average have chosen low-paid jobs in which workers enjoy the freedom of entering and leaving the labor force, which reduces their years of experience relative to men. Other people say the gap can also be explained by the difference in educational background.

Much of the gap, however, has not been fully explained. It might be the result of some prejudice (偏见) against women. It is this part that has produced calls for government action. What would happen if the government did intervene to increase the wages paid to women? One possibility is that incomes for women as a group might actually decline (下降). An increase in wage decreases the quantity of labor imput demanded, resulting in decreased employment as the rate of hiring r~ew workers declines. The result will be a surplus (过剩) of labor. Those who can find jobs might be better off while those who had jobs might find themselves out of work.

The difference in labor incomes is most obvious between ______.

A．young men and young women

B．young women in the same industry

C．middle-aged men and middle-aged women

D．middle-aged women in the same industry