单选题Exposure to asbestos fibres is harmful to people' s health ______.

单选题Einstein, like other great physicists before him, worked out new theories that challenge our ______ concept of the universe. A. existed B. established C. organized D. adjusted

单选题The salesman approached the house cautiously when he saw the vicious dog at the door.

单选题You will be late ______ you leave immediately.A. unlessB. untilC. ifD. or

单选题 The common cold is the world's most widespread illness, which is probably why there are more myths about it than any of the other plagues (瘟疫) that flesh is heir to. The most widespread fallacy (谬误，谬论) of all is that colds are caused by cold. They are not. They are caused by viruses passed on from person to person. You catch a cold by coming into contact, directly or indirectly, with someone who already has one. If cold causes colds, it would be reasonable to expect the Eskimos to suffer from them permanently. But they do not. And in isolated arctic regions explorers have reported being free from colds until coming into contact again with infected people from the outside world by way of packages and mail dropped from airplanes. During the First World War soldiers who spent long periods in the trenches, cold and wet, showed no 'increased' tendency to catch colds. In the Second World War prisoners at the notorious Auschwitz concentration camp, naked and starving, was astonished to find that they seldom had colds. At the Common Cold Research Unit in England, volunteers took part in experiment in which they submitted to the discomforts of being cold and wet for long stretches of time. After taking hot baths, they put on bathing suits, allowed themselves to be doused (浸泡) with cold water, and then stood about dripping wet in drafty rooms. Some wore wet socks all day while others exercised in the rain until close to exhaustion. Not one of the volunteers came down with a cold unless a cold virus was actually dropped in his nose. If, then, cold and wet have nothing to do with catching colds, why are they more prevalent in the winter? Despite the most painstaking research, no one has yet found the answer. One explanation offered by scientists is that people tend to stay together indoors more in cold weather than at other time, and this makes it easier for cold viruses to be passed on. No one has yet found a cure for the cold. There are drugs and pain suppressors such as aspirin, but all they do is relieve the symptoms.

单选题Don"t poke your nose into what doesn"t ______ you.

单选题Desert plants ______ two categories according to the way they deal with the problem of surviving drought.

单选题We first think of the traditional or nuclear family. This is a two-generation family, the father and the mother and their own children. Most couples wanted to have four children, two boys, two girls. Some nuclear families, however, may add one or more grandparents to come to live with them, that is three generations. This kind of family with grandparents, parents, and grandchildren is called an extended family. This family type was not very common during the later half of the twentieth century, but it's becoming more common now as an elderly grandparent moves in to live with a son or daughter. This is more possible now that American homes have become larger. What is interesting, however, is that after the grandchildren move out of the home and start their own families, this extended family shrinks back to a nuclear family, with just two generations again living together, a grandparent and parents, with the grandchildren coming only for occasional visits. Now, the fatherless or motherless family is one kind of what we call a single-parent family. In the fatherless family it's just the mother and her children. As I said, this can be the result of the husband's death, of an unmarried mother, of a separation or divorce. There are also a growing number of motherless families--where the father raises the children, for any of the same reasons. A motherless family may also be fatherless, but still a family with one adult. This is becoming more common in the big cities where a grandmother will raise her daughter's children while the daughter goes elsewhere to work. One other new kind of family is becoming increasingly more common. A single parent with one or more children will marry again. Perhaps the other parent is also a single parent. Together they will start what is called a blended family, which blends together or combines the children from two other families.

单选题The comments which he made ______ marketing bothered his boss greatly.

单选题Having seen the movie adapted from an American novel, ______.

单选题Man: I'm sorry I missed the football game, but I had a terrible cold. Woman: You didn't miss anything. We couldn't have played worse. Question: What does the woman mean?

单选题His______ should not be confused with cowardice; during the war, I saw him on several occasions risk his own life while rescuing members of his unit.

单选题According to the Constitution, any national agreement has to be ____ by a two-thirds majority in parliament.

单选题If you carefully ______ the problem again, you will find a way out.

单选题I found this very profitable in diminishing the intensity of narrow-minded prejudice.

单选题It is much easier to talk about social change than to ______.

单选题To speed up the _____ of letters, the Post Office introduced automatic sorting.

单选题John says that his present job does not provide him with enough ______ for his organizing ability.

单选题The value of the industrial ______ dropped from about 70 billion dollars to slightly more than 31 billion.

单选题Mrs. James is seeking a divorce from her husband, for she can no longer ______ his stormy temper.