题目内容
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What is the principal constituent of natural gas？
A．Carbon and hydrogen.
B．Methane and other hydrocarbon gases.
C．Saturated hydrocarbons.
D．Non-associated gas.
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When We Are Asleep
Everyone dreams, but some people never recall their dreams, or do so very rarely. Other people always wake up with vivid recollections (记忆 ) of their dreams, though they forget them very quickly. In an average night of eight hours&39;sleep, an average adult will dream for around one hundred minutes, probably having three to five dreams, each lasting from ten to thirty minutes.
Scientists can detect when someone is having a dream by using an instrument which measures the electrical waves in the brain. During dreaming, these waves move more quickly. Breathing and pulse rate also increase, and there are rapid eye movements under the lids, just as though the dreamer were really looking at moving objects. These signs of dreaming have been detected in all mammals (哺乳动物) studied, including dogs, monkeys, cats, and elephants, and also some birds and reptiles (爬行动物) .This period of sleep is called the "D" state for around 50% of their sleep; the period reduces to around 25% by the age of 10.
Dreams take the form. of stories, but they may be strange and with incidents not connected, which make little sense. Dreams are seldom without people in them and they are usually about people we know. One estimate says that two-thirds of the "cast" of our dream dramas are friends and relations. Vision seems an essential part of dreams, except for people blind from birth. Sound and touch senses are also often aroused, but smell and taste are not frequently involved. In "normal" dreams, the dreamer may be taking part, or be only an observer. But he or she cannot control what happens in the dream.
However, the dreamer does have control over one type of dream. This type of dream is called a "lucid"(清醒的) dream. Not everyone is a lucid dreamer. Some people are occasional lucid dreamers. Others can dream lucidly more or less all the time. In a lucid dream, the dreamer knows that he is dreaming.
Some people dream but cannot remember their dreams. 查看材料
A.Right
B.Wrong
C.Not mentioned
A、Use inclusive language.
B、Use natural and spoken language.
C、Ask questions.
D、Learn to emphasize.
E、Show your opinion.
A、supplies
B、accumulates
C、gathers
D、yields
A、by
B、of
C、with
D、for
The riches of the sea yet to be developed by man ’s technology are impressive. Oil and gas explorations have existed for nearly thirty years. Valuable amounts of minerals such as iron, nickel and copper and so on exist on the ocean floor, ready to be mined.
Fish farming promises to be a good way to produce large quantities of food. The culture of fish and shellfish is an ancient skill practiced in the past mainly by Oriental peoples.
Besides oil and gas, the sea may offer new sources of energy. Experts believe that the warm temperature of the ocean can be used in a way similar to the steam in a steamship. Ocean currents and waves offer possible use as a source of energy such as hydroelectric power.
Technology is enabling man to explore ever deeper under the sea. The new undersea technology is providing divers with diving suits and undersea chambers that are kept at sea level pressure. The development of strong, new materials has made this possible.
The technology to harvest the sea continues to improve. By the year 2000, experts believe that the problems to exploit the food, minerals, and energy sources of the sea will be largely solved.
What is the best title for the passage？
A.Needs of .Man
B.Sources of..Energy
C.Sea Harvest
D.Sea Exploring Technology
According to the author, technology for exploring the sea is important because______.A.man cannot travel farther into space
B.resources on land are running short
C.it’s a lot of fun diving into the sea
D.ancient people used to explore the sea
Why does the author mention a steamship？A.To indicate that it is warmer in the ocean than on land.
B.To show that a steamship is better than other kinds of ship.
C.To argue that man should use steamships more than other means of transportation.
D.To illustrate that man can make use of sources of energy from the sea.
It can be inferred from the passage that_______.A.man hasn’t completely developed the riches of the sea
B.technology for exploring the sea has been solved
C.planting rice in the sea will be made possible in a short time
D.in the near future man can live on the ocean floor
The word “exploit” in the last paragraph could best be replaced by________.A.evaluate
B.develop
C.gather
D.scatter
A、a second
B、eight minutes
C、an hour
D、a year
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