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When we analyze the salt salinity盐浓度 of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are threebasic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since thesalt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.
The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted 稀释 so that the salinity is decreased. This may occur inareas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of freshwater by precipitation.
Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, incoastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.
A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind.. In this manner,seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of thesurrounding water.
In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in thedeeper portion of the oceans of the world.
26. This passage mainly tells us about_______.
A. the analysis of the salinity of ocean waters
B. the causes of the variation in oceanic salinity
C. the importance of the changes in oceanic salinity
D. the different forms of salts in ocean waters
27.It can be known from the passage that increase in the salinity of ocean water is caused
by______.
A. melting of sea ice B. precipitation
C. evaporation D. supplement of salt
28.Which of the following is not the cause of the decrease in the oceanic salinity?
A. Precipitation. B. Rain and snow.
C. Formation of ice. D. Addition of water by rivers.
29.Which of the following statements is TRUE according to the passage?
A. Oceanic salinity has great effect on sea life.
B. Many factors combine to cause changes in oceanic salinity.
C. The movement of the water is related to the amount of salt.
D. The temperature of the water has much to do with the oceanic salinity.
30.The purpose of mentioning the Weddell Sea is_______.
A. to give an example of cold-water salinity
B. to point out the location of deep waters
C. to make a comparison between hot-water salinity and cold-water salinity
D. to show that the water in the Weddell Sea varies in salinity from place to place
答案：
26. B 27. C 28. C 29. D 30. A
It is well known that when an individual joins a group he tends to accept the group's standards of behavior and thinking. Many illustrations 例证 could be given of this from everyday life,but what is of particular interest to psychologists is the extent to which people's judgments and opinions can be changed as a result of group pressure. Asch and others noticed that people in agroup will agree to statements that are contrary to the evidence of their senses. It would be a mistake to think that only particular changeable people are chosen to take part in experiments ofthis type. Usually highly intelligent and independent people are used.
In a typical experiment, this is what may happen. The experimenter asks for volunteers to join a group which is investigating visual perception. The victims are not, therefore, aware of thereal purpose of the experiment. Each volunteer is taken to a room where he finds a group of about seven people who are collaborating合作 with the experimenter. The group is shown a standardcard which contains a single line. They are then asked to look at a second card. This has three lines on it. One is obviously longer than the line on the first card, one is shorter and one thesame length. They have to say which line on the second card is the same length as the line on the standard card. The other members of the group answer first but what the volunteer does not knowis that they have been told to pick one of the wrong lines. When his turn comes he is faced with the unanimous 一致的opinion of the rest of the group—all the others have chosen line A but hequite clearly sees line B as correct. What will he do? According to Asch, more than half of the victims chosen will change their opinion. What is equally surprising is that, when interviewedabout their answers, most explained that they know the group choice was incorrect but that they yield to the pressure of the group because they thought they must be suffering from an opticalillusion, or because they were afraid of being different.
26. The psychologists are particularly interested in_______.
A. the changes in the attitudes of the people
B. the degree of changes of people's opinions
C. the result of the experiment
D. the difference in people's characters
27. People who are usually chosen to take part in the experiments are_______.
A. stubborn and independent B. intelligent
C. ignorant and docile D. capable of reasoning
28. Which of the following statements is TRUE?
A. The experimenter and all the members of the group except the victim know the purpose of the experiment.
B. All of them know the purpose of the experiment.
C. Only the experimenter knows the purpose of the experiment.
D. Only the victim knows the purpose of the experiment.
29. More than half of the victims changed their opinion because_______.
A. someone in the group changed their opinion
B. they thought their eyes must be deceived
C. they thought the group choice was correct.
D. they had been told about the answer
30. The purpose of the author in writing this passage is to_______.
A. illustrate the influence of the group's pressure on individual's behavior
B. invite more volunteers to join in Asch's experiment
C. tell the audience how to perform psychological experiment
D. encourage people to act against the group's opinion
答案
26. B 27. D 28. C 29. B 30. A
