题目内容
Doctors and other scientists have concluded that ______ .
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In the late 1960s many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized: Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking tot capacities.
Skyscrapers are also lavish comsumers, and wasters of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120,000 kilowattsenough to supply the entire city of Albany, New York, for a day.
Glass-walled skyscrapers can be especially wasteful. The beat loss (or gain) through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air-conditioning equipment, builders of skyscrapers have begun to use double glazed panels of glass, and reflective glasses coated with sih/er or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.
Skyscrapers put a severe strain on a city's sanitation facilities, too. (If fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-- as much as a city the size of Stanford, Connecticut, which has a population of more than 109,000. )
Skyscrapers also interfere with television reception, block bird flyways, and obstruct air traffic. In Bos ton in the late 1960s, some people even feared that shadows from skyscrapers would kill the grass on Boston Common.
Still, people continue to build skyscrapers for all the reasons that they have always built them--person al ambition , civic pride, and the desire of owners to have the largest possible amount of rentable space.
The main purpose of the passage is to ______.
The nuclear energy is released at the Sun’s center as high - energy gamma radiation, a form. of electro magnetic radiation like light and radio waves only of very much shorter wavelength. This gamma radiation is absorbed by atoms inside the Sun, to be reemitted at slightly longer wavelengths. This radiation, in its turn, is absorbed and reemitted. At the energy filters through the layers of the solar interior, it passes through the X - ray part of the spectrum, eventually becoming light. At this stage, it has reached what we call the solar sur face, and can escape into space, without being absorbed farther by solar atoms. A very small fraction of the Sun's light ,ma heat is emitted in such directions that, after passing unhindered through interplanetary space, it hits the Earth.
A simple magnifying glass, focusing the Sun’s rays, can scoarch, a piece of wood or set a Scrap of paper on fire. Solar radiation can also be concentrated on a much larger scale. It can burn a hole through thick steel plate, for example, or simulate the thermal shock of a nuclear blast. It can, that is, with the help of a super reflector of the sort that has been set up by French scientists high in the Pyreness. The world’s largest solar furnace is a complex of nearly 20,000 mirrors. It can concentrate enough sunlight to create temperatures in excess of 6000 degrees Fahrenheit.
The furnace’s appearance is as spectacular as its power. Its glittering eight - story - high reflector towers over very old houses. Anchored against a concrete office and laboratory building, the huge reflector consists of nearly 9000 separate mirrors. For the furnace to operate, these small mirrors must be adjusted so that their light will meet exactly at a focal point 59 feet in front of the giant reflector.
What does the passage mainly discuss？
It's important to remember that nutrients have to work ______, and to take too much of one
SECTION B INTERVIEW
Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Questions 1 to 5 are based on an interview. At the end of the interview you will be given 10 seconds to answer each of the following five questions.
Now listen to the interview.
听力原文：Chairwoman: Ladies and gentleman. May I have your attention please？ My name is Mary Smith, and I'm going to chair this morning’s opening session. It is my greatest pleasure this morning towel come you, my colleagues from all over the world, to our 16th biennial Cryogenic Engineer lng Conference held jointly for the nineth time in succession with the International Cryogenic Materials Conference.
Our keynote speaker at the morning’s plenary session will be Dr Scott Macleod from Canada. Dr Macleod will review our accomplishments in the field of cryogenics on its 110th birthday, and consider where our work will lead in the future. Following Dr Macleod’s keynote address, we will be honoured to hear from Dr Chen Zhili from the People’s Republic of China. Dr Chen will speak on "The Development of Cryogenic Materials Science in the PRC over the Last Decade', a matter of great significance to the world scientific community as you are all very well aware.
We will have a coffee break at 10 a. m. and at 10:30 a. m. the first set of workshop sessions will begin. Please Check your conference brochuse programme summary for work shop room locations. One additional point, at the request of several of our colleagues from abroad, a special workshop has been set up un der the heading: "Concrete Plans for Implementing Greater International Cooperation on Research Projects. "The session will take place in the Teawood suite on the fourth floor at 8:00 tomorrow morning. Dr Saul Lloy from MIT has kindly agreed to chair that meeting.
Voice I: Would you repeat that information, please？
Chairwoman: Yes. That’s tomorrow morning at 8:00 in the Teawood Suite on the fourth floor. Dr Lloy pre siding .... And now ladies and gentlemen, this morning’s presentation from Dr Scott Macleod. (Applause)
Macleod: Thank you, Ms Chairwoman, Ladies and gentle men. One hundred and ten years after Lois Cailletet in France and Raoul Dictete in Switzerland produced our first cryogens, we have experienced significant accomplishments and identified many opportunities. This morning I will highlight our accomplishments in the field of thermal insulations... (Applause)
Chairwoman :Thank you, Professor Macleod. Since we' re a little late, I'll ask you to save your questions and comments on professor Macleod’s paper for the "History of Cryogenics' workshop this afternoon. And now I’d like to introduce to you our next speaker, Dr. Chen Zhili. His history, like so many Chinese scientists today, is a dramatic one, and his personal story parallels the dynamic achievements of his nation in the past decade. But that’s the topic of his speech to day. So I' II let him speak for himself. I present you Dr Chen Zhili. (Applause)
Chen: Good morning, ladies and gentlemen. I shall first ask for your forgiveness of my poor English since I haven't been in the States for several years. Then I’d like to thank Ms Chairwoman and the conference Committee for offering me this opportunity to speak to you on a subject which is dear to my heart. It is with great pride and pleasure that I stand before you today to report the progress of my nation in the last decade in the area of Cryogenic materials science, though we are the first to point out that it were not for the generosity and aid of other nations during this period we could not have come so far so fast. In the last decade, we have suffered several setbacks, yet we have still made some breakthroughs. And today I' m going to talk on these breakthroughs... (Applause)
Chairwoman: Thank you very much, Professor Chen, yours was indeed an enlightening overview and
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