大学英语四级模拟试题及答题详解.docx

1、大学英语四级模拟试题及答题详解大学英语四级模拟试题及答题详解 Part I Reading Comprehension （Skimming and Scanning） （15 minutes） Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For questions 1 - 7, mark Y （for YES） if the statement agrees with the inform

2、ation given in the passage; N （for NO） if the statement contradicts the information given in the passage; NG （for NOT GIVEN）if the information is not given in the passage. For questions 8 - 10, complete the sentences with the information given in the passage. Sleep Sleep is one of those funny things

3、 about being a human being - you just have to do it. Have you ever wondered why? And what about the crazy dreams, like the one where a bad person is chasing you and you cant run or yell. Does that make any sense? Characteristics of Sleep When we see someone sleeping, we recognize the following chara

4、cteristics: If possible, the person will lie down to go to sleep. The persons eyes are closed. The person doesnt hear anything unless it is a loud noise. The person breathes in a slow, rhythmic pattern. The persons muscles are completely relaxed. If sitting up, the person may fall out of his or her

5、chair as sleep deepens. During sleep, the person occasionally rolls over or rearranges his or her body. This happens approximately once or twice an hour. This may be the bodys way of making sure that no part of the body or skin has its circulation cut off for too long a period of time. In addition t

6、o these outward signs, the heart slows down and the brain does some pretty funky things. In other words, a sleeping person is unconscious to most things happening in the environment. The biggest difference between someone who is asleep and someone who has fainted or gone into a coma is the fact that

7、 a sleeping person can be aroused if the stimulus presented by is strong enough. If you shake the person, yell loudly or flash a bright light, a sleeping person will wake up. Who Sleeps? Reptiles（爬行动物）， birds and mammals all sleep. That is, they become unconscious to their surroundings for periods o

8、f time. Some fish and amphibians （两栖动物） reduce their awareness but do not ever become unconscious like the higher vertebrates（脊椎动物） do. Insects do not appear to sleep, although they may become inactive in daylight or darkness. By studying brainwaves, it is known that reptiles do not dream. Birds dre

9、am a little. Mammals all dream during sleep.Different animals sleep in different ways. Some animals, like humans, prefer to sleep in one long session. Other animals like to sleep in many short bursts. Some sleep at night, while others sleep during the day. Sleep and the Brain If you attach an electr

10、oencephalograph to a persons head, you can record the persons brainwave activity. An awake and relaxed person generates alpha waves, which are consistent oscillations at about 10 cycles per second. An alert person generates beta waves, which are about twice as fast. During sleep, two slower patterns

11、 called theta waves and delta waves take over. Theta waves have oscillations in the range of 3.5 to 7 cycles per second, and delta waves have oscillations of less than 3.5 cycles per second. As a person falls asleep and sleep deepens, the brainwave patterns slow down. A person deep in delta wave sle

12、ep is hardest to wake up. REM Sleep At several points during the night, something unexpected happens - rapid eye movement （REM） sleep occurs. Most people experience three to five intervals of REM sleep per night, and brainwaves during this period speed up to awake levels. If you ever watch a person

13、or a dog experiencing REM sleep, you will see their eyes flickering back and forth rapidly. In many dogs and some people, arms, legs and facial muscles will twitch during REM sleep. Periods of sleep other than REM sleep are known as NREM （non-REM） sleep. REM sleep is when you dream. If you wake up a

14、 person during REM sleep, the person can vividly recall dreams. If you wake up a person during NREM sleep, generally the person will not be dreaming. You must have both REM and NREM sleep to get a good nights sleep. A normal person will spend about 25 percent of the night in REM sleep, and the rest

15、in NREM. A REM session a dream - lasts five to 30 minutes. When You Miss Some Zzzzs One way to understand why we sleep is to look at what happens when we dont get enough: As you know if you have ever pulled an all-nighter, missing one night of sleep is not fatal. A person will generally be irritable

16、 during the next day and will either slow down （become tired easily） or will be totally wired because of adrenalin （肾上腺素）。 If a person misses two nights of sleep, it gets worse. Concentration is difficult, and attention span falls by the wayside. Mistakes increase. After three days, a person will st

17、art to hallucinate and clear thinking is impossible. With continued wakefulness a person can lose grasp of reality. Rats forced to stay awake continuously will eventually die, proving that sleep is essential. A person who gets just a few hours of sleep per night can experience many of the same probl

18、ems over time. Two other things are known to happen during sleep. Growth hormone in children is secreted during sleep, and chemicals important to the immune system are secreted during sleep. You can become more prone to disease if you dont get enough sleep, and a childs growth can be stunted（阻碍） by

19、sleep deprivation. Why Sleep? No one really knows why we sleep. But, there are all kinds of theories, including these: Sleep gives the body a chance to repair muscles and other tissues, replace aging or dead cells, etc. Sleep gives the brain a chance to organize and archive memories. Dreams are thou

20、ght by some to be part of this process. Sleep lowers our energy consumption, so we need three meals a day rather than four or five. Since we cant do anything in the dark anyway, we might as well turn off and save the energy.What we all know is that, with a good nights sleep, everything looks and fee

21、ls better in the morning. Both the brain and the body are refreshed and ready for a new day. Dreams The brain creates dreams through random electrical activity. Random is the key word here. About every 90 minutes the brain stem sends electrical impulses throughout the brain, in no particular order o

22、r fashion. The analytic portion of the brain - the forebrain-then desperately tries to make sense of these signals. It is like looking at a Rorschach test, a random splash of ink on paper. The only way of comprehending it is by viewing the dream （or the inkblot） metaphorically, symbolically, since t

23、heres no literal message. This doesnt mean that dreams are meaningless or should be ignored. How our forebrains choose to analyze the random and discontinuous images may tell us something about ourselves, just as what we see in an inkblot can be revelatory. And perhaps there is a purpose to the craz

24、iness: Our minds may be working on deep-seated problems through these circuitous and less threatening metaphorical dreams. Here are some other things you may have noticed about your dreams: Dreams tell a story. They are like a TV show, with scenes, characters and props. Dreams are egocentric. They a

25、lmost always involve you. Dreams incorporate things that have happened to you recently. They can also incorporate deep wishes and fears. A noise in the environment is often worked in to a dream in some way, giving some credibility to the idea that dreams are simply the brains response to random impu

26、lses. You usually cannot control a dream - in fact, many dreams emphasize your lack of control by making it impossible to run or yell. Dreaming is important. In sleep experiments where a person is woken up every time he/she enters REM sleep, the person becomes increasingly impatient and uncomfortabl

27、e over time. How Much Sleep Do I Need? Most adult people seem to need seven to nine hours of sleep a night. This is an average, and it is also subjective. You, for example, probably know how much sleep you need in an average night to feel your best. The amount of sleep you need decreases with age. A

28、 newborn baby might sleep 20 hours a day. By age four, the average is 12 hours a day. By age 10, the average falls to 10 hours a day. Senior citizens can often get by with six or seven hours a day. 1. This passage tells us why people have to sleep and what causes dreams. 2. During sleep, the person

29、is conscious to most things happening in the environment. 3. Neither reptiles nor birds dream during sleep. 4. A normal person spends the main part of the night in NREM sleep. 5. If you miss one night of sleep, you will lose your appetite to some extent. 6. Nobody really knows the reason why we slee

30、p. 7. Generally speaking, you need less amount of sleep as you grow older. 8. The slower , the deeper the sleep.9. REM in this passage stands for _. 10. The brain stem sends electrical impulses throughout the brain about every _ Part IV Reading Comprehension （Reading in Depth） （25 minutes） Section A

31、 Directions: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once. Questions 47 to 56 are based on the following passage.