AIDS-like Disease Found in Monkeys

　　An international group of scientists has found evidence that wild chimpanzees infected with Simian Immunodeficiency Virus - once considered harmless to the apes - can develop a deadly AIDS-like syndrome. Researchers say the discovery could lead to new treatments for HIV, the virus that causes AIDS in humans.

　　It has long been thought that SIV - the monkey virus that was the original source of the human immunodeficiency virus - was a mild disease, and that chimpanzees and other non-human primates(灵长类) infected with SIV could live for decades without developing AIDS symptoms.

　　But researchers studying a large group of wild chimpanzees in Gombe National Park in Tanzania report SIV-infected chimps experienced immune system failure and were much more likely than uninfected apes to die prematurely.

　　The research was led by Beatrice Hahn, a professor of medicine and microbiology at the University of Alabama in Birmingham, and a specialist in the evolution and genetics of immune deficiency viruses in primates.

　　Hahn says it significant that chimps can develop AIDS just like people infected with HIV-1, one of two viral strains that jumped the species barrier to humans.

　　"Chimpanzees are 98 percent genetically identical to humans," said Beatrice Hahn. "And their viruses are very closely related to HIV-1 because it was, in fact, the source. So, this similarity was attractive in terms of figuring out what the differences are. But the assumption was that chimps do not get sick, people do get sick. Well, that is no longer true. Chimps do get sick as well."

　　Researchers observed 94 SIV-infected and uninfected chimps at the start of the study a decade ago. Eighteen of the chimps developed AIDS, and seven died of the disease.

　　Overall, the researchers found chimpanzees infected with SIV were 10 to 16 times more likely to die prematurely compared to uninfected chimps. They also gave birth to lower-weight offspring and had a higher infant mortality rate

　　1.Which of the following statements is NOT true about SIV according to the passage

　　A.It was once considered harmless to apes.

　　B.It has long been thought to be the original source of HIV.

　　C.No chimps has ever had AIDS caused by SIV.

　　D.SIV can cause AIDS in apes

　　正确答案:C

　　解析:问题问的是：以下哪个关于SIV(猿猴免疫缺乏病毒)的说法是不真实的?文章倒数第二段中提到被观察的94只带有SIV的黑猩猩中，有18只得了AIDS。因此C“没有黑猩猩得过AIDS”的说法不真实

　　2.The underlined word “prematurely”(Line3, Para. 3) probably means

　　A.earlier than it is supposed to be.

　　B.not grown up.

　　C.with great agony.

　　D.at the right age

　　正确答案:A

　　解析:问题问的是：第三段中带下划线的单词“prematurely”是什么意思?这个词是“过早地”，因此A正确

　　3.In Paragraph 6, Hahn denies

　　A.Chimpanzees are very close to humans in genetic structure.

　　B.SIV is actually the source of HIV-1.

　　C.Chimps infected with SIV don’t develop AIDS.

　　D.Chimps infected with SIV can develop AIDS

　　正确答案:C

　　解析:问题问的是：第六段中哈恩否认什么?第六段中哈恩称“人会因HIV而得上AIDS，而黑猩猩不会因SIV而得上AIDS”的假设已经不是真的了。因此选C。注意题中“denies”一词是“否认”的意思，理解该词才可能选对

　　4.What is the approximate percentage of chimps which died of AIDS among the observed in the study a decade ago

　　A.7%.

　　B.15%.

　　C.20%.

　　D.28%.

　　正确答案:A

　　解析:问题问的是：实验观察中，黑猩猩死于AIDS的比例大约是多少?倒数第二段中说94只黑猩猩中有7只死于AIDS，因此百分比大约是7%

　　5.We can learn from the passage that

　　A.SIV is a mild disease that does really matter to chimps.

　　B.chimps infected with SIV are at a higher risk of death than the others.

　　C.the babies of the chimps infected with SIV are not likely to be born dead.

　　D.SIV and HIV are exactly the same thing

　　正确答案:B

　　解析:问题问的是：从文章中我们能了解到什么?A“SIV对于黑猩猩没有影响”显然不对;C“感染SIV的黑猩猩生出的孩子不可能夭折。”与最后一段最后一句中的“higher infant mortality rate”即“更高的婴儿死亡率”矛盾。D“SIV和HIV是完全一样的”也不正确，文中只提到了它们非常相似，但不能说完全一样。因此选C