Read the following passage and mark the letter A, B, C or B on your answer sheet to indicate the correct answer to each of the questions from 30 to 37.
Pollution is a threat to many species on Earth, but sometimes it can cause species to thrive. Such is the case with Pfiesteria piscicida. A one-celled creature called a dinoflagellate, Pfiesteria inhabits warm coastal areas and river mouths, especially along the eastern United States. Although scientists have found evidence of Pfiesteria in 3,000-year-old sea floor sediments and dinoflagellates are thought to be one of the oldest life forms on earth, few people took notice of Pfiesteria.
Lately, however, blooms – or huge, dense populations – of Pfiesteria are appearing in coastal waters, and in such large concentrations the dinoflagellates become ruthless killers. The blooms emit powerful toxins that weaken and entrap fish that swim into the area. The toxins eventually cause the fish to develop large bleeding sores through which the tiny creatures attack, feasting on blood and flesh. Often the damage is astounding. During a 1991 fish kill, which was blamed on Pfiesteria on North Carolina’s Neuse River, nearly one billion fish died and bulldozers had to be brought in to clear the remains from the river. Of course, such events can have a devastating effect on commercially important fish, but that is just one way that Pfiesteria causes problems. The toxins it emits affect human skin in much the same way as they affect fish skin. Additionally, fisherman and others who have spent time near Pfiesteria blooms report that the toxins seem to get into the air, where once inhaled they affect the nervous system, causing severe headaches, blurred vision, nausea, breathing difficulty, short-term memory loss and even cognitive impairment.
For a while, it seemed that deadly Pfiesteria blooms were a threat only to North Carolina waters, but the problem seems to be spreading. More and more, conditions along the east coast seem to be favorable for Pfiesteria. Researchers suspect that pollutants such as animal waste from livestock operations, fertilizers washed from farmlands and waste water from mining operations have probably all combined to promote the growth of Pfiesteria in coastal waters.
In which enviromnent would you NOT expect a Pfiesteria bloom to develop?
A. a marsh which absorbs waste water from a nearby pig farm
B. a river located near a rock quarry
C. a cool mountain lake teeming with fish
D. a river that flows through rich farmland
Giải bởi qa.haylamdo.com
Đáp án C
Trong môi trường nào mà bạn KHÔNG mong đợi sự phát triển của Pfiesteria?
A. một đầm lầy hút nước thải từ một trại nuôi lợn gần đó
B. một dòng sông gần mỏ đá
C. một hồ trên dãy núi mát mẻ có đầy cá
D. một dòng sông chảy qua vùng đất nông nghiệp phong phú
Dẫn chứng: Pfiesteria inhabits warm coastal areas and river mouths
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Without _________ all the resources necessary for life would be damaged, wasted or destroyed.
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_________ some Japanese women are successful in business, the majority of Japanese companies are run by men.
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No player except the _________ can hold the ball with two hands.
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Daisy’s parents don’ t let her go to late - night disco. She _________ be at home at 9 o’clock in the evening.
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“Excuse me; can I book a ticket for Paris?” “ _________ ”
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Government have passed laws to _________ protect wildlife from commercial trade.
Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.
“Can I get you something to drink?” “ _________ I’m thirsty.”
Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
There is no excuse for your discourtesy. Think twice before you are going to say anything.
Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
Mutalism is a type of symbiosis that occurs when two unlike organisms live together in a state that is mutually beneficial.
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Ernest Hemingway is one of my _________ American writers.
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He began to feel ill while _________.
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In certain industries the workers' apparel is not only cumbersome but also quite heavy.
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Tom is saving up _________he can buy a new car.
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Ben made all attempts to carry out the project. Finally, he completed it with satisfactory result
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By 2015, it will be widely accepted that schools and pre-schools have _________extremely important role to play in _________future of our world.
