Passage One
Unlike the scientist, the engineer is not free to select the problem which interests him;he must solve the problems as they arise, and his solutions must satisfy conflicting requirements. Typically, the engineering solution to most problems must take into account many factors.
To the engineer, efficiency means output divided by input. His job is to secure a maximum output for a given input or to secure a given output with a minimum input. The ratio may be expressed in terms of energy, materials, money, time, or man. Most commonly the denominator (分母) is money;in fact, most engineering problems are answered ultimately in dollars and cents.
The emphasis on efficiency leads to the large, complex operations which are characteristic of engineering. The processing of the new antibiotic and vaccines in the test-tube stage belongs in the field of biochemistry, but when great quantities must be produced at low cost, it becomes an engineering problem. It is the desire for efficiency and economy that distinguishes ceramic engineering from the work of the potter, textile engineering from weaving, and agricultural engineering from farming.
Since output equals input minus losses, the engineer must keep losses and waste to a minimum. One way is to develop uses for products which otherwise would be waste. The work of the chemical engineer in utilizing successively greater fractions of raw materials such as crude oil is well known. Losses due to friction occur in every machine and in every organization. Efficient functioning depends on good design, careful attention to operating difficulties, and lubrication of rough spots, whether they are mechanical or personal.
The raw materials with which engineers work are seldom found in useful forms. Engineering of the highest type is required to conceive, design, and achieve the conversion of the energy of a turbulent mountain stream into the powerful torque(转矩) of an electric motor a hundred miles away. Similarly many engineering operations are required to change the sands of the seashore into the precise lenses which permit us to observe the minute bacteria in a drop of water and study a giant mass of stars in outer space.

52. What might be inferred about the scientist from the sentences at the beginning of the text?
A) He must choose the long-term solution to a problem.
B) He may study the problem he has an interest in.
C) He can avoid the conflict between work and pleasure.
D) He should be familiar with some engineering problems.

53. In the second paragraph, the word "ratio" refers to ______.
A) minimum input divided by maximum output
B) given input divided by maximum output
C) output divided by input
D) money divided by output
54. According to the passage, the processing of the new antibiotic and vaccines becomes an engineering problem when ______.
A) it involves the low-cost production of large quantities
B) these items originate in the work of biochemistry
C) people are engaged in safe operations in the test-tube stage
D) business agents use efficient methods to market these items

55. Which of the following can be best answered by the information about the reduction of losses and waste in engineering?
A) When do losses and waste soar in a machine?
B) Why is the work of the chemical engineer important to oil refining?
C) How does the engineer achieve the good design of a product?
D) What are essential for the efficient functioning of a machine?
56. The organization of the last paragraph can be best described as ______.
A) following the time order B) from specific to general
C) cause and effect D) statement and examples

52--56 BCADD
52.推断题。第一段第一句话“Unlike the scientist，the engineer is not free to select the problem which interests him”反过来说就是：“Unlike the engineer, the scientist is free to select the problem which interests him.”。故正确答案为B项。
53.词义推断题。由上下文“...efficiency means output divided by input...The ratio may be expressed in terms of...”可以看出ratio(比率)即“投入和产出比”，故正确答案为C项。
54.细节选择题。由第三段第二句“The processing of the new antibiotic and vaccines in the test-tube stage belongs in the field of biochemistry，but when great quantities must be produced at low cost，it becomes an engineering problem”可知正确答案为A项。
55.意义理解题。由第四段第一句“Since output equals input minus losses...”可知控制loss和waste，则output增加，则ratio=output/input值增大，效率提高。第四段后半部分也提到“Efficient functioning depends on good design，careful attention to operating difficulties，and lubrication of rough spots”，即效率取决于好的设计、摩擦减少等，也就是控制loss和waste，故正确答案为D项。
56.由最后一段“The raw materials with which engineers work are seldom found in useful forms.Engineering of the highest type is required to conceive，design，and achieve the conversion of the energy of...into...Similarly...change the sands into...”可知，工程就是把看似无用的原材料转变为对人类有用的东西。然后举例说明，比如让山间急流转动百里外的发电机，把海滩沙砾变成望远镜观察太空等。