【C9】A．in whichB．with whichC．for whichD．of which

【C9】

A．In

B．On

C．To

D．At

【C9】

A．in red

B．in rags

C．with colors

D．with uniform

e and pressure commonly found【C2】______of the Earth. A liquid can be kept in an open container and【C3】______it to the level of a free surface. A gas forms no free surface but【C4】______to diffuse throughout the space available; it must【C5】______be kept in a closed container, as【C6】______a planet's atmosphere. The distinction was a【C7】______feature of early theories【C8】______the phases of matter. In the nineteenth century, for example, one theory maintained that a liquid could be "dissolved" in a vapor without losing its identity, and another theory held that the two phases are【C9】______different kinds of molecules(分子). The theories now prevailing【C10】______a quite different approach by emphasizing.【C11】______liquids and gases have in common. They are both forms of matter that have no permanent structure, and they both【C12】______easily. They are fluids.

The【C13】______similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat.【C14】______a closed container partially filled with a liquid is heated. The liquid expands, or【C15】______, becomes less dense; some of it evaporates.【C16】______, the vapor above the liquid surface becomes denser as the evaporated molecules are【C17】______it. The combination of temperature and pressure【C18】______the densities become equal is【C19】______the critical point. Above the critical point the liquid and the gas can no longer be【C20】______; there is a single, undifferentiated fluid phase of uniform. density.

【C1】

A．in

B．on

C．under

D．beyond

only for the purpose of educating them; our purpose is to fit them for life.【C1】______we realize this fact, we will understand that it is very important to【C2】______a system of education which will really prepare children for life.

In many modern countries it has【C3】______been accepted that, by free education for all-whether rich or poor, clever or stupid-we can solve【C4】______of society and build a【C5】______nation. But we can already see that free education for all is not【C6】______: we find in such countries【C7】______people with university degrees than【C8】______jobs for them to do. Because of their degrees, they refuse to do what they think "low" work.

But we have only to think for a moment to understand that the work of a completely uneducated【C9】______is far more important than【C10】______we can live【C11】______education, but we【C12】______ if we have no food. If no one cleaned our streets and took the【C13】______away from our houses, we【C14】______terrible diseases in our towns.

In fact,【C15】______we say that all of us must be educated to fit us for life, it means that we must be educated【C16】______that each of us can do whatever job【C17】______him, and that we can realize that all jobs are【C18】______to society, and that it is very bad to be ashamed to do one's work, or to laugh at【C19】______. Only such a type of education can be【C20】______valuable to society.

【C1】

A．In order that

B．Before

C．As soon as

D．Though

am a tailor, it will net be【C1】______convenient for me always to have to exchange the clothes I make for other goods or services. A doctor may went to buy a coat from me, but I may not need medical【C2】______so he will then have to find【C3】______else that I want, or look for another tailor who needs him.【C4】______money, the tax-collector would come back to his office with au extraordinary collection of【C5】______.

Considered as a【C6】______of storing up buying power, money has good and bad points. It can more【C7】______be kept a long time【C8】______such things as food, which rots, or buildings, which slowly【C9】______to pieces, or machines, which rust. It takes up very little【C10】______, and if you put it in a bank, it is as【C11】______as anything in this world can be.

But modern money has some very【C12】______disadvantages as a means of storing up buying【C13】______. In the old days, when money was in the【C14】______of geld and silver coins, the metal in each was really【C15】______the amount stamped on the coin. But the paper in modem paper money and even the metal in most modem coins are worth less than the【C16】______written on them.【C17】______, the buying power of modem money can change very greatly【C18】______a short time.

It has happened more than once this century that the buying power of a country's money has fallen to almost【C19】______in a few weeks,【C20】______many thousands of people with savings.

【C1】

A．in mm

B．by chance

C．at all

D．on average

They may have trouble eating or sleeping. They suffer【C1】______a condition known as Seasonal Affective Disorder, or SAD.

【C2】______of SAD【C3】______its effects during the short, dark days of【C4】______. The problems are most【C5】______in the months when there are fewer hours of daylight. When spring arrives, these signs【C6】______and SAD victims feel【C7】______again.

The National Mental Health Association reports that SAD can【C8】______anyone. The group says young people and women are【C9】______the highest risk for the disorder. It says that an estimated twenty-five percent of the American population suffers from some form. of SAD. About five percent suffer from a severe form. of the【C10】______.【C11】______, many people in other parts of the world also have the condition.

To treat the disorder, victims of SAD do not need to wait until【C12】______. Experts know that【C13】______affected individuals【C14】______bright light each day【C15】______the condition.【C16】______, there are other things people can do to ease the problem. They can【C17】______the sunlight in their homes and workplaces. They can spend【C18】______time outdoors in the fresh air during the day.

One study found that walking for an hour in winter sunlight was as【C19】______as spending two-and-one-half hours in【C20】______light indoors.

【C1】

A．in

B．from

C．at

D．with

A.unhappy

B.desperate

C.unlucky

D.excited