PCR can be applied to sequence a human genome.

A humanlike robot developed has the ability ______.

A．to speak and hear

B．to see and feel

C．to solve problems

D．the passage doesn't say

A．A whale.

B．A snail.

C．A snake.

D．A human.

What will the student most probably do now?

A．Return later in the day to see the woman in the admissions office

B．Go to the office for transfer students to be assigned an advisor

C．Enter information in the computer to complete the application process

D．See the woman's superior to get a provisional admission to State University

Sleep

Sleep is one of those funny things 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 per son is chasing you and you can't run or yell. Does that make any sense?

Characteristics of Sleep

When we see someone sleeping, we recognize the following characteristics:

If possible, the person will lie down to go to sleep.

The person's eyes are closed.

The person doesn't hear anything unless it is a loud noise.

The person breathes in a slow, rhythmic pattern.

The person's muscles are completely relaxed. If sitting up, the person may fall out of his or her 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 body's 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 to 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 a sleeping person can be aroused if the stimulus 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(哺乳动物)all sleep. That is, they become unconscious to their surroundings for periods of time. Some fish and amphibians reduce their aware ness but do not ever become unconscious like the higher vertebrates 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 dream 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 electroencephalograph to a person's head, you can record the person's 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 a bout twice as fast.

During sleep, two slower patterns 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 brain wave patterns slow down. A person deep in delta wave sleep 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 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 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 night's sleep. A normal person will spend about 25 percent of the night in REM sleep, and the rest in NREM. A REM session -- a dream -- lasts five to 30 minutes.

When You Miss Som

A．Y

B．N

C．NG

Whether or not animals feel is not altogether an easy question to answer. A human being has direct awareness only of the pains which he himself suffers. Our knowledge of the pains even of other beings is only an inference from their words, and to a lesser extent their behaviour. Animals cannot tell us what they feel. We can, of course, study their bodily reactions to the kind of stimuli which would be painful to human beings and this has often been done. When such stimuli are applied to animals their pupils dilate, their pulse rate and blood pressure rise, they may withdraw the stimulated limb and they may make struggling movements. Nevertheless it has been pointed out that none of these reactions can safely be taken as indication that the animal experiences pain because they can all be evoked when the parts of the body stimulated have been isolated from the higher nervous centres. Furthermore, when disease produces such an isolation in human beings the corresponding stimuli are painless. We must therefore look for other evidence as to the capacity of animals to experience pain.

Basically, all the nervous elements which underlie the experience of pain by human beings are to be found in all mammalian vertebrates at least; this is hardly surprising as pain is a response to a potentially harmful stimulus and is therefore of great biological importance for survival. Is there any reason, then, for supposing that animals, though equipped with all the necessary neurological structures, do not experience pain? Such a view would seem to presuppose a profound qualitative difference in the mental life of animals and men, the difference between the human and subhuman nervous system lies chiefly in the much greater development of the human fore-brain. This would be significant in the present context only if there were reason to believe that it alone was correlated with the occurrence of conscious experiences. But much of our knowledge of the nervous regulation of consciousness is derived from experiments on animals.

Nevertheless, we cannot tell what pain means to an animal. We know from our own experience that pains differ greatly in their quality, severity and emotional accompaniments. We know, too, that experiences which in man would be fraught with intense and prolonged emotion cause only brief and fleeting disturbances in animals. The great development of the human forebrain is the basis of man's capacity for foresight, apprehension, and memory which so profoundly affects his experiences. It would be rash, therefore, to conclude that the pain which animals feel can be in all respects equated with that which human beings experience.

Which of the following is the best title for the text?

A．Animals and Pain

B．Human Beings and Pain

C．Painful Stimuli and Reactions

D．Nerve System and Pain

What time will be suitable(合适的) for the lawyer to see the man?

A．Monday.

B．Thursday.

C．Wednesday.