Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
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 seafloor 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, fishermen 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 wastewater from mining operations have probably all combined to promote the growth of Pfiesteria in coastal waters.
What is true of Pfiesteria?
A. It seems to flourish in the presence of certain pollutants
B. It has been a menace to fish and humans for over 3000 years.
C. It is the oldest life form on earth.
D. In large concentrations, it poses a threat to fish but not to humans.
Giải bởi Vietjack
Đáp án đúng: A
Giải thích: Ta có thể thấy ở câu “Pollution is a threat to many species on Earth, but sometimes it can cause species to thrive.”
Dịch: Ô nhiễm là mối đe dọa đối với nhiều loài trên Trái đất, nhưng đôi khi nó có thể khiến một số loài phát triển mạnhA_____is a book, film, or play that tells an exciting fictional story about something such as criminal activities or spying,
Current extinction rates are at least 100 to 1,000 times higher than____ rates found in the fossil record.
Women's status____in different countries and it depends on the cultural beliefs.
I think the match____ Everybody's gone into the stadium and you can hear them cheering.
What is the main function of the toxins emitted by the dinoflagellates?
Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
Peter told us about his leaving the school. He did it on his arrival at the meeting.
Life on Earth is disappearing fast and will continue to do so unless urgent action is taken.
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.
Founded after World War II by 51 "peace-loving states" combined to oppose future aggression, the United Nations now counts 192 member nations, (17)___its newest members, Nauru, Kiribati, and Tonga in 1999, Tuvalu and Yugoslavia in 2000, Switzerland and East Timor in 2002, and Montenegro in 2006.
United Nations Day has been (18)___on October 24 since 1948 and celebrates the objectives and accomplishments of the organization, which was established on October 24, 1945.
The UN (19)____in peacekeeping and humanitarian missions across the globe. Though some say its (20) ______has declined in recent decades, the United Nations still plays a tremendous role in world politics. In 2001 the United Nations and Kofi Annan, then Secretary-General of the UN, won the Nobel Peace Prize "for their work for a better organized and more peaceful world.
Since 1948 there have been 63 UN peacekeeping operations that are currently underway. Thus far, close to 130 nations have contributed personnel (21)_____various times; 119 are currently providing peacekeepers. As of August 31, 2008, there were 16 peacekeeping operations underway with a total of 88,230 personnel. The small island nation of Fiji has taken part in virtually every UN peacekeeping operation, as has Canada.Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
__we invested in the telecommunication industry, we would be rich by now.
Mark the letter A, B, C or D to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
I couldn't make out what he had talked about because I was not used to his accent
Mark the letter A, B, C or D to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
She was unhappy that she lost contact with a lot of her old friends when she went abroad to study.
My brother has given up smoking. He used to____20 cigarettes a day.
