Question 49. What does the passage mainly discuss?
A. Marine pollution and its many forms.
B. Noise and its disruptive effects on marine life.
C. Various kinds of harmful pollutants.
D. The end of the "dilution" era.
Question 50. The word "negligible" in paragraph 1 is closest in meaning to ____.
A. serious B.insignificant C. unpredictable D.positive
Question 51. It can be inferred from paragraph 2 that the "dilution" policy is related to _______.
A. dealing with the problems of water pollution
B. helping the ecosystem of the oceans flourish
C. neglecting the effects of dumping trash into the oceans
D. treating harmful materials in the oceans properly
Question 52. The word "they" in paragraph 4 refers to _______.
A. ocean's depths B. man-made pollutants
C.marine organisms D. the oceans
Question 53. The word "spawn" in paragraph 5 can be best replaced by _______.
A. appear B.prevent C. produce D. limit
Question 54.According to the passage, nitrogen-rich fertilizers _______.
A. are created by massive blooms of algae
B. cause a shortage of oxygen in the ocean water
C. do not relate to the disappearance of marine life
D.cannot be found inland
Question 55. Which of the following statements is NOT supported in the passage?
A. Many pollutants deposited in the oceans finally become part of the global food chain.
B. It is apparent that the oceans have been polluted for a long time.
C. Industrial wastes and agricultural run-off are blamed for the degradation of the oceans.
D. The oceans in the past were more contaminated than they are now.
Question 56. Whales and dolphins are mentioned in the final paragraph as an example of marine creatures that _______.