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[单选题]

Since the beginning of history, people have hoped for___ travel.

A.mutualplanetary

B.interplanetary

C.crossplanetary

D.betweenplanetary

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更多“Since the beginning of history…”相关的问题

第1题

Since the beginning of last year, these regulations _____ in most workplaces across

Since the beginning of last year, these regulations _____ in most workplaces across the city.

A、be introduced

B、will be introduced

C、have introduced

D、have been introduced

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第2题

Since the early 1980s, scientists have revealed some 40 human genes involved in cancer. Th

ese genes are essential for normal growth, but can be subverted to cause a tumor.

Dr. Jorge Yunis of the University of Minnesota Medical School in Minneapolis has found that 70 percent of oncogenes, or cancer-causing genes, are located near inherited weak points on chromosomes(染色体). Varying from individual to individual, vulnerable to chemical carcinogens(致癌剂), X rays and other cancer-inducing agents.

"If a chromosome snaps apart in the immediate vicinity of an oncogene," says Yunis, "normal genetic control mechanisms could break down and the stage would be set for the formation of cancer." Younis has shown that such a sequence occurs at the beginning of numerous leukemias (白血病), lymphomas(淋巴瘤) and some tumors of the lung, colon(结肠) and breast.

Yunis and other investigators have found that petroleum-based products--notably pesticides and insecticides-damage specific sites on at least two of the 23 pairs of human chromosomes that carry genetic information. Similarly, tobacco smoke tends to attack a part of another chromosome.

From paragraph 1, we know that some 40 genes involving in cancer are ______. ()

A．harmful to the human body

B．necessary to the human body

C．the elements that form. cancer

D．useless to the human body

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第3题

Milk has become a popular drink for modem Chinese, not only is its nutritional（营养的) val

Milk has become a popular drink for modem Chinese, not only is its nutritional(营养的) value appreciated, it seems even to have taken the role making the whole nation strong. Milk industry has only about 180 years of history among the Hah people. For a long time, milk was considered a luxury(奢侈的) drink by common people. A widespread saying in the country was that Japan used a cup of milk to strengthen the constitution(体格) of its people. That sounds reasonable because the rich "Ca" in milk definitely benefits the constitution.

The average annual consumption per capita in Japan has risen from less than 10 kilograms immediately after World War II to 68 kilograms today. The average height of Japanese has increased by 11 centimeters during this period. The Chinese Government also hopes to improve the constitution of local people, and since milk is the most obvious nutritious food, it has naturally been picked up. But due to tradition, Chinese people are not in the habit of drinking milk regularly. The annual output of milk in the country is about 10 million tons, compared with an output of alcohol reaching 8 million tons. The annual milk consumption per capita is about 7 kilograms in China while the world's average is about 100 kilograms. The government has noticed the huge gap and plans to raise consumption to 10 kilograms per capita by 2005 and 16 kilograms by 2010. The government has also started plans for "school milk" since the beginning of this century.

Chinese government encourage people to drink milk and hope that ______.

A．the whole nation will become stronger

B．the milk industry will have a faster development

C．milk will no longer be considered a luxury drink

D．its nutritional value will be more appreciated

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第4题

听力原文："Where is the university？ is question many visitors to Cambridge ask, but no one

听力原文： "Where is the university？ is question many visitors to Cambridge ask, but no one could point them in any one direction because there is no campus. The university consists of thirty-one self-governing colleges. It has lecture halls, libraries, laboratories, museums and offices throughout the city(32).

Individual colleges choose their own students (33), who have to meet the minimum entrance requirements set by the university. Undergraduates usually live and study in their colleges, where they are taught in very small groups. Lectures, and laboratory and practical work are organized by the university and held in university buildings.

There are over ten thousand undergraduates and three thousand five hundred postgraduates. About 40% of them are women and some 8% from overseas. As well as teaching, research is of major importance. Since the beginning of the twentieth century, more than sixty university members have won Nobel prizes.

The university has a huge number of buildings for teaching and research. It has more than sixty specialist subject libraries, as well as the University Library, which, as a copyright library, is entitled to a copy of every book published in Britain(34).

Examinations are set and degrees are awarded by the university. It allowed women to take the university exams in 1881, but it was not until 1948 that they were awarded degrees(35).

(33)

A．Because there are no signs to direct them.

B．Because no tour guides are available.

C．Because all the buildings in the city look alike.

D．Because the university is everywhere in the city.

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第5题

Rivers are one of our most important natural resources （资源). Many of the world&39;s grea

Rivers are one of our most important natural resources (资源). Many of the world&39;s great cities are located(坐落) on rivers, and almost every country has at least one river running through it that plays an important role in the lives of its people.

Since the beginning of the history, people have used rivers for transportation(运输). The longest one in the United States is the Mississippi. The lifeline of Egypt is the Nile. To the people of India, the Gangs is great, but it is also important for transportation; Ships can travel along it for a thousand miles. Other great rivers are the Congo in Africa and the Mekong in southeast Asia. The greatest of all for navigation (航海), however, is the Amazon in Brazil. It is so wide and so deep that large ships can go about two thousand miles upon it.

Besides transportation, rivers give food, water to drink, water for crops(庄稼), and chances for fun and entertainment for the people who live along their banks. In order to increase(增加) the supply of crops, engineers sometimes build a dam (大坝) across a river and let a lake from behind the dam. Then people can use the water not only to irrigate (灌溉) their fields but also to make electricity for their homes and industries.

However, large cities and industries that are located upon rivers often make problems. As the cities grow in size and industries increase in number, the water in the rivers becomes polluted with chemicals(化学物质) and other materials. People are learning the importance, however, of doing more to keep their rivers clean if they want to enjoy the benefits (利益) of this natural resource.

The greatest river for navigation is ___________.

A.the Amazon

B.the Nile

C.the Mekong

D.the Mississippi

From a dam, people can use the water for ___________.A.keeping the rivers clean

B.only making electricity

C.washing clothes

D.irrigation and making electricity

The water in the river is polluted because of _____________.A.people's drinking water too much

B.people's swimming in the river too much

C.chemicals and other materials