Questions 31 to 35 are based on the following passage.

　　It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.

　　So biologists were delighted early this year when, with the help of the Navy, they were able to track a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy’s formerly top-secret system of underwater listening devices spanning the oceans.

　　Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies.

　　Earth scientists announced at a news conference recently that they had used the system for closely monitoring a deep-sea volcanic eruption (爆发) for the first time and that they plan similar studies.

　　Other scientists have proposed to use the network for tracking ocean currents and measuring changes in ocean and global temperatures.

　　The speed of sound in water is roughly one mile a second—slower than through land but faster than through air. What is most important, different layers of ocean water can act as channels for sounds, focusing them in the same way a stethoscope (听诊器) does when it carries faint noises from a patient’s chest to a doctor’s ear. This focusing is the main reason that even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thousands of miles.

　　31. The passage is chiefly about ________.

　　A) an effort to protect an endangered marine species

　　B) the civilian use of a military detection system

　　C) the exposure of a U.S. Navy top-secret weapon

　　D) a new way to look into the behavior of blue whales

　　32. The underwater listening system was originally designed ________.

　　A) to trace and locate enemy vessels

　　B) to monitor deep-sea volcanic eruptions

　　C) to study the movement of ocean currents

　　D) to replace the global radio communications network

　　33. The deep-sea listening system makes use of ________.

　　A) the sophisticated technology of focusing sounds under water

　　B) the capability of sound to travel at high speed

　　C) the unique property of layers of ocean water in transmitting sound

　　D) low-frequency sounds traveling across different layers of water

　　34. It can be inferred from the passage that ________.

　　A) new radio devices should be developed for tracking the endangered blue whales

　　B) blue whales are no longer endangered with the use of the new listening system

　　C) opinions differ as to whether civilian scientists should be allowed to use military technology

　　D) military technology has great potential in civilian use

　　35. Which of the following is true about the U.S. Navy underwater listening network?

　　A) It is now partly accessible to civilian scientists.

　　B) It has been replaced by a more advanced system.

　　C) It became useless to the military after the cold war.

　　D) It is indispensable in protecting endangered species

Passage Four

　　Questions 36 to 40 are based on the following passage.

　　The fitness movement that began in the late 1960s and early 1970s centered around aerobic exercise (有氧操). Millions of individuals became engaged in a variety of aerobic activities, and literally thousands of health spas developed around the country to capitalize (获利) on this emerging interest in fitness, particularly aerobic dancing for females. A number of fitness spas existed prior to this aerobic fitness movement, even a national chain with spas in most major cities. However, their focus was not on aerobics, but rather on weight-training programs designed to develop muscular mass, strength, and endurance in their primarily male enthusiasts. These fitness spas did not seem to benefit financially form the aerobic fitness movement to better health, since medical opinion suggested that weight-training programs offered few, if any, health benefits. In recent years, however, weight training has again become increasingly popular for males and for females. Many current programs focus

　　not only on developing muscular strength and endurance but on aerobic fitness as well.

　　Historically, most physical-fitness tests have usually included measures of muscular strength and endurance, not for health-related reasons, but primarily because such fitness components have been related to performance in athletics. However, in recent years, evidence has shown that training programs designed primarily to improve muscular strength and endurance might also offer some health benefits as well. The American College of Sports Medicine now recommends that weight training be part of a total fitness program for healthy Americans. Increased participation in such training is one of the specific physical activity and fitness objectives of Healthy People 2000: National Health Promotion and Disease Prevention Objectives.

　　36. The word “spas” (Line 3, Para. 1) most probably refers to ________.

　　A) sports activities

　　B) places for physical exercise

　　C) recreation centers

　　D) athletic training programs

　　37. Early fitness spas were intended mainly for ________.

　　A) the promotion of aerobic exercise

　　B) endurance and muscular development

　　C) the improvement of women’s figures

　　D) better performance in aerobic dancing

　　38. What was the attitude of doctors towards weight training in health improvement?

　　A) Positive.

　　B) Indifferent.

　　C) Negative.

　　D) Cautious.

　　39. People were given physical fitness tests in order to find out ________.

　　A) how ell they could do in athletics

　　B) what their health condition was like

　　C) what kind of fitness center was suitable for them

　　D) whether they were fit for aerobic exercise

　　40. Recent studies have suggested that weight training ________.

　　A) has become an essential part of people’s life

　　B) may well affect the health of the trainees

　　C) will attract more people in the days to come

　　D) contributes to health improvement as well

　　Unit 7

　　21. C 22. A 23. A 24.D 25.C

　　26. B 27. D 28. C 29.A 30. B

　　31. B 32. A 33. C 34.D 35. A

　　36. B 37. B 38. C 39.A 40. D