Questions 21 to 25 are based on the following passage.
More and more, the operations of our businesses, governments, and financial institutions are controlled by information that exists only inside computer memories. Anyone clever enough to modify this information for his own purposes can reap substantial rewards. Even worse, a number of people who have done this and been caught at it have managed to get away without punishment.
It’s easy for computer crimes to go undetected if no one checks up on what the computer is doing. But even if the crime is detected, the criminal may walk away not only unpunished but with a glowing recommendation from his former employers.
Of course, we have no statistics on crimes that go undetected. But it’s disturbing to note how many of the crimes we do know about were detected by accident, not by systematic inspections or other security procedures. The computer criminals who have been caught may been the victims of uncommonly bad luck.
For example, a certain keypunch (键盘打孔) operator complained of having to stay overtime to punch extra cards. Investigation revealed that the extra cards she was being asked to punch were for dishonest transactions. In another case, dissatisfied employees of the thief tipped off (向…透露) the company that was being robbed.
Unlike other lawbreakers, who must leave the country, commit suicide, or go to jail, computer criminals sometimes escape punishment, demanding not only that they not be charged but that they be given good recommendations and perhaps other benefits. All too often, their demands have been met.
Why? Because company executives are afraid of the bad publicity that would result if the public found out that their computer had been misused. They hesitate at the thought of a criminal boasting in open court of how he juggled (耍弄) the most confidential records right under the noses of the company’s executives, a accountant, and security staff. And so another computer criminal departs with just the recommendations he needs to continue his crimes elsewhere.

21. It can be concluded from the passage that ________.
A) it is still impossible to detect computer crimes today
B) computer crimes are the most serious problem in the operation of financial institutions
C) computer criminals can escape punishment because they can’t be detected
D) people commit computer crimes at the request their company
22. It is implied in the third paragraph that ________.
A) many more computer crimes go undetected than are discovered
B) the rapid increase of computer crimes is a troublesome problem
C) most computer criminals are smart enough to cover up their crimes
D) most computer criminals are smart enough to cover up their bad luck
23. Which of the following is mentioned in the passage?
A) A strict law against computer crimes must be enforced.
B) Companies need to impose restrictions on confidential information.
C) Companies will guard against computer crimes to protect their reputation.
D) Companies usually hesitate to uncover computer crimes.
24. What may happen to computer criminals once they are caught?
A) With a bad reputation they can hardly find another job.
B) They will be denied access to confidential records.
C) They may walk away and easily find another job.
D) They must leave the country or go to jail.
25. The passage is mainly about ________.
A) why computer crimes are difficult to detect by systematic inspections
B) why computer criminals are often able to escape punishment
C) how computer criminals manage to get good recommendation from their former employers
D) why computer crimes can’t be eliminated
   Questions 26 to 30 are based on the following passage.
It is often claimed that nuclear energy is something we cannot do without. We live in a consumer society where there is an enormous demand for commercial products of all kinds. Moreover, an increase in industrial production is considered to be one solution to the problem of mass unemployment. Such an increase presumes an abundant and cheap energy supply. Many people believe that nuclear energy provides an inexhaustible and economical source of power and that it is therefore essential for an industrially developing society. There are a number of other advantages in the use of nuclear energy. Firstly, nuclear power, except for accidents, is clean. A further advantage is that a nuclear power station can be run and maintained by relatively few technical and administrative staff. The nuclear reactor represents an enormous step in our scientific evolution and, whatever the anti nuclear group says, it is wrong to expect a return to more primitive sources of fuel. However, opponents of nuclear energy point out that nuclear power stations bring a direct threat not only to the environment but also to civil liberties.
Furthermore, it is questionable whether ultimately nuclear power is a cheap source of energy. There have, for example, been very costly accidents in America, in Britain and, of course, in Russia. The possibility of increases in the cost of uranium (铀) in addition to the cost of greater safety provisions could price nuclear power out of the market. In the long run, environmentalists argue, nuclear energy wastes valuable resources and disturbs the ecology to an extent which could bring about the destruction of the human race. Thus, if we wish to survive, we cannot afford nuclear energy. In spite of the case against nuclear energy outlined above, nuclear energy programmes are expanding. Such an expansion assumes a continual growth in industrial production and consumer demands. However, it is doubtful whether this growth will or can continue. Having weighed up the arguments on both sides, it seems there are good economic and ecological reasons for sources of energy other than nuclear power.

26. The writer’s attitude toward nuclear energy is ________.
A) indifferent
B) favorable
C) tolerant
D) negative
27. According to the opponents of nuclear energy, which of the following is true of nuclear energy?
A) Primitive
B) Exhaustible
C) Cheap
D) Unsafe
28. Some people claim that nuclear energy is essential because ________.
A) it provides a perfect solution to mass unemployment
B) it represents an enormous step forward in our scientific evolution
C) it can meet the growing demand of an industrially developing society
D) nuclear power stations can be run and maintained by relatively few technical and administrative staff
29. Which of the following statements does the writer support?
A) The demand for commercial products will not necessarily keep increasing.
B) Nuclear energy is something we cannot do without.
C) Uranium is a good source of energy for economic and ecological reasons.
D) Greater safety provisions can bring about the expansion of nuclear energy programmes.
30. The function of the last sentence is to ________.
A) advance the final argument
B) reflect the writer’s attitude
C) reverse previously expressed thoughts
D) show the disadvantages of nuclear power