单选题When the concentration of calcium in the blood is too low, the parathyroid glands began to secrete the hormone parathormone.

单选题Project Hond Start which was {{U}}inaugurated{{/U}} in the United States in 1965 is a federally funded preschool for economically and culturally disadvantaged children.

单选题A UN official said that aid programs would be ______ until there was adequate protection for relief convoy.(2005年电子科技大学考博试题)

单选题Using many symbols makes ______ to put a large amount of information on a single map.

单选题What if our society uses new-found technologies of "genetic engineering" to interfere with the biological nature of human beings? Might that not be disastrous? What about cloning, for instance? Cloning is a term originally used in connection with nonsexual reproduction of plants and very simple animals. Now it is coming into use in connection with higher animals, since biologists are finding ways of starting with an individual cell of a grown animal and inducing it to multiply in the same way in the future. But is cloning a safe thing to unleash on society? Might it not be used for destructive purposes? For instance, might not some ruling group decide to clone their submissive, downtrodden peasantry, and thus produce endless hordes of semi-robots who will slave to keep a few in luxury and who may even serve as endless ranks of soldiers designed to conquer the rest of the world? A dreadful thought, but an unnecessary fear. For one thing, there is no need to clone for the purpose. The ordinary method of reproduction produces all the human beings that are needed and as rapidly as is needed. Right now, the ordinary method is producing so many people as to put civilization in danger of imminent destruction. What more can cloning do? Secondly, unskilled semi-robots cannot be successfully pitted against the skilled users of machine, either on farms, in factories or in armies. Any nation depending on downtrodden masses will find itself an easy mark for exploitation by a less populous but more skilled and versatile society. This has happened in the past often enough. But even if we forget about self-hordes, what about the cloning of a relatively few individuals? There are rich people who could afford the expense, or politicians who could have the influence for it, or the gifted who could undergo it by popular demand. There can be two of a particular banker or governor or scientist—or three—or a thousand. Might this not create a kind of privileged caste, who would reproduce themselves in greater and greater numbers, and who would gradually take over the world? Before we grow concerned about this, we must ask whether there will really be any great demand for cloning. Would you want to be cloned? The new individual that is formed by your cell will have your genes and therefore your appearance and, possibly, talents, but he will not be you. The clone will be, at best, merely your identical twin. Identical twins share the same genetic pattern, but they each have their own individuality and are separate persons. Cloning is not a pathway to immortality, then, because your consciousness does not survive in your clone, any more than it would in your identical twin if you had one. In fact, your clone would be far less than your identical twin. What shapes and forms a personality is not genes alone, but all the environment to which it is exposed. Identical twins grow up in identical surroundings, in the same family, and under each other"s influence. A clone of yourself, perhaps thirty or forty years younger would grow up in a different world altogether and would be shaped by influences that would be sure to make him less and less like you as he grows older. He may even earn your jealousy. After all, you are old and he is young. You may once have been poor and struggled to become well-to-do, but he will be well-to-do from the start. The mere fact that you won"t be able to view him as a child, but as another competing and better-advantaged you, may accentuate the jealousy. No! Imagine that, after some initial experiments, the demand for cloning will be virtually nonexistent.

单选题Theinventionofthetelephonewasagreat____tocommunication.

单选题A(An) ______ is a person who knows a great deal about a particular subject and whose advice on it may be taken by others.

单选题You are exposed to obtrusive ads that ______ seemingly from nowhere even when you are disconnected from the Net, and your personal information gathered and sent off without you being aware of it.

单选题A fourth grader can work at a fifth-grade level in math and a third-grade level in English without the stigma associated with being left back or the pressures of being skipped ahead.

单选题Brazilian music is thoroughly imbued with African themes, and illustrious composers have long found inspiration in the black musical heritage.

单选题Members of parliament are ______ by the people.

单选题According to the author, if you want to keep healthy, you had better ______.

单选题This policy gave ______ to private property and led to differences between the rich and the poor.(2002年上海交通大学考博试题)

单选题The work is not very profitable ______ cash, but I am getting valuable experience from it.

单选题The most famous painter in Victoria's history is Emily Carr. When she was a child, she discovered that walking in the woods【C1】______more to her than playing with other children, and that she was more interested in【C2】______the streets of old Victoria than playing at home with【C3】______and spending her time making up. Emily was a cute little girl who spent【C4】______of her childhood in Beacon Hill Park, 【C5】______was very close to her home. Drawing【C6】______her, and she also liked to play with the pets. She had ducks and chickens, and even【C7】______a monkey. She was【C8】______interested in the First Nations people and the Chinese people she saw in Victoria's Chinatown. Their culture and way of dressing seemed so【C9】______from her own. As she became a young, strong and【C10】______woman, Emily began to go on long trips into the forests to【C11】______and draw what she saw. She loved the free and simple【C12】______of the First Nations people. In the summer of 1895 she went on【C13】______with two other women to 【C14】______the wilderness along the Cowichan River that runs through Duncan, 【C15】______north of Victoria. She knew more about their lifestyle and the forests of B. C. than【C16】______other European woman. When you look at her paintings, you can sense the【C17】______of these dark, mysterious forests. Her paintings are now very famous and, 【C18】______the dark colors may not be attractive to some people, they【C19】______the beauty and mystery of the deep woods and the skill of a great artist. Emily was a very brave and independent woman. She walked through the woods alone, even though she knew that bears and wolves might be her only【C20】______.

单选题The team's efforts to score were ______ by the opposing goalkeeper. A. surpassed B. doubled C. frustrated D. furthered

单选题To cream a circuit, a conducting wire is attached to an electric cell at one end, and to an electric Uoutlet/U at the other.

单选题(Having finis) heal high school, the village education board (appointed) him (to) a teaching post (in) the primary school.

单选题Pigeon is the common name for members of a family of birds; smaller species are commonly known as doves, but sizes of pigeons and doves______. The birds, almost worldwide in distribution, are most abundant in warm regions.