更多"DIAPHANOUS : LIGHT ::"的相关试题:
[单项选择]A. Light skin with gray hair. B. Light skin with dark hair.
C. Light skin with blonde hair. D. Dark skin with dark hair.
[单项选择]LIGHT : COLOR ::
A. radiation: temperature
B. celerity : span
C. quality : quantity
D. sound : pitch
E. (E) strength : stress
[填空题]
Electromagnetic Energy
White
light seems to be a combination of all colors. The energy that comes from a
source of light is not limited to the kind of energy you can see. Heat is given
off by a flame or an electric light. On a cloudy day it is possible to get a
sunburn even though you feel cool. Visible light and the kind of energy that
produce warmth and sunburn are examples of electromagnetic energy.
The sun is 93 million miles from the earth. Yet we can use energy from
the sun because electromagnetic energy travels through space.
Many other kinds of energy are also types of electromagnetic energy. Radio,
television, and radar signals travel from transmitters to receivers as
low-energy electromagnetic waves, infrared (红外线的) radiation is an
electromagnetic wave. When it is absorbed by matter, heat is produced. Waves of
infrared and visible light have more energy than waves of radio, television, or
radar. Ultraviolet rays (紫外线) and X-rays are electromagnetic waves with even
greater amounts of energy. Infrared radiation is used in cooking food and
heating buildings. Sunlight and electric lights are part of our requirements for
normal living. Ultraviolet radiation is useful in killing certain disease
organisms. X-rays and gamma rays have so mush energy that they travel right
through solid objects. They can be used to detect and treat cancer. X-rays are
used in industry to find hidden cracks in metal, and in medicine to reveal
broken bones.
Usually we use electricity to generate
electromagnetic energy. The source of most of our energy is the sun. Heat from
the sun causes water to evaporate. When the water falls to the earth as rain,
some of it is trapped behind dams and then used to operate electric generators.
Other generators are powered by coal, but the energy stored in coal came from
the sun, too.
Until recently, the source of the tremendous
amount of energy given off by the sun was a puzzle. If the sun depended on
chemical reactions, it would have used up all its energy long ago. Experiments
with electromagnetic radiation led to the theory that mass can be converted into
energy. About forty years after the theory was proposed, nuclear energy was
harnessed (利用) by man. Chemical energy comes from electron (电子) rearrangement.
Nuclear energy comes from a change in the nucleus of an atom. Compared with
chemical reactions, nuclear reactions release millions of times more energy per
pound of fuel. We now believe that the sun’s energy comes from the nuclear
reactions in which hydrogen is changed into helium (氦).
Nuclear
energy is beginning to compete with coal as an economical source of power to
generate electricity. It is also being used to operate engines in large ships.
Scientists continue to seek new and better methods of obtaining and using
energy.Paragraph 3 ______.
A. Nuclear reactions as the lasting source of the sun’s energy
B. The most important source of energy
C. Types of electromagnetic energy
D. The machines used for energy generation
E. Seeking new sources of energy
F. The use of ultraviolet radiation in medicine
[单项选择]Crew chiefs supervised engines, switches and lights that told them how each item of equipment was functioning.（ ）
A. observed
B. preserved
C. monitored
D. nurtured
[单选题]If the aircraft in radio failure receives light signals provided by the controller during daytime, he should acknowledge tower transmission or light signals by _______ .
A.rocking the wings
B.blinking the landing light or navigation lights
C.rocking the wings first and then blinking the landing light
D.blinking the navigation lights
[单项选择]Why is light coloring an advantage to large desert animals
A. It helps protect them from other dangerous animals.
B. It keeps them cool during the day.
C. It keeps them warm by reflecting light.
D. It helps them maintain a constant body temperature.
[填空题]Vent life dies quickly when exposed to light.
[单项选择]The first recorded use of natural gas to light street lamps it was in the town of Frederick, New York, in 1825.
A. was
B. is
C. it is
D. were
[单项选择]The light is still on. Why not （）
A. turn it on
B. turn it off
C. turn on it
D. turn off it
[单项选择]Light goes three quarters of the way from the earth to the noon in one second．（）
A. 光一秒钟以后能走完25%的路程、从地球到月球。
B. 光一秒钟可以走过地球至月球距离的75%。
C. 光一秒钟可以走过地球至月球距离的四分之三。
D. 光一秒钟可以通过地球到月球距离的四分之三。
[单项选择]
London’s First Light Rail System
The Docklands Light Railway (DLR) took just three years to build at a cost of ￡77 million. It is London’s first Light Rail System, but its route follows that of a number of older lines, which carried the nineteenth century railways through the crowded districts of the East End.
The section of the line from the Tower Gateway Station to Poplar follows the line of one of London’s earliest railways, the London&Blackwell (1840), a cable-drawn railway (later converted to steam) which carried passengers to steam ships at Blackwell Pier, and provided transport for the messengers and clerks who went backwards and forwards between the docks (码头) and the city every day.
From Poplar to Island Gardens, a new line crosses high above the dock waters, and then joins the old track of the Millwall Extension Railway, built to service the Millwall Docks (1868) and to provide transport for workers in the local factor
A. now carries passengers to and from the docks.
B. was a busy line a few years ago.
C. used to employ many messengers and clerks.
D. was not originally a steam railway.
[单项选择]There is no light in the dormitory. They must have gone to the lecture, ______
