Excerpt 1 : The process of vaccination allows the patient’s body to develop immunity to the virus or disease so that, if it

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问题     Excerpt 1 :
    The process of vaccination allows the patient’s body to develop immunity to the virus or disease so that, if it is encountered, one can ward it off naturally. To accomplish this, a small weak or dead strain of the disease is actually injected into the patient in a controlled environment, so that his body’s immune system can learn to fight the invader properly. Information on how to penetrate the disease’s defenses is transmitted to all elements of the patient’s immune system in a process that occurs naturally, in which genetic information is passed from cell to cell.
    Excerpt 2:
    Scientists are hoping to eliminate malaria(疟疾)by developing a genetically modified mosquito that cannot transmit the disease. Malaria has long troubled the populations of South America, Africa, and Asia, where mosquito bites infect 500 million people a year with this serious and sometimes fatal parasitic blood disease. For generations, scientists have been trying to eliminate malaria by developing new drugs and using pesticide (杀虫剂) to wipe out local mosquito populations. But these measures aren’t working...and some scientists, like Greg Lanzaro, say that because of drug resistance and population changes, malaria is actually more prevalent now than it was 20 years ago.
    Excerpt 3:
    Gene therapy and gene-based drugs are two ways we could benefit from our growing mystery of genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years.
    While it’s true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so-called stem cells haven’t begun to specialize.
    Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells—brain cells in Alzheimer’s, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few; if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue.
    Excerpt 4:
    For years, pediatricians didn’t worry much about treating hypertension in their patients. After all, kids grow so fast, it’s hard keeping up with their shoe sizes, let alone their blood pressure. Sure, hypertension in adults places them at greater risk of heart attack and stroke. But nobody likes the idea of starting youngsters on blood-pressure medicine they could wind up taking the rest of their lives. Who knows what previously unheard-of side effects could crop up after five or six decades of daily use?
    Excerpt 5:
    From the health point of view we are living in a marvelous age. We are immunised from birth against many of the most dangerous diseases. A large number of once illnesses can now be cured by modern drugs and surgery. It is almost certain that one day remedies will be found for the most stubborn remaining diseases.
    Excerpt 6:
    Cardiologists have pioneered the world’s first non-surgical bypass operation to turn a vein into an artery using a new technique to divert blood flow in a man with several heart diseases; the keyhole procedure, which avoids the extensive invasive surgery of a conventional bypass, will offer hope to tens of thousands of people at risk from heart attacks.
    Coronary heart disease, where the arteries are progressively silted up with fatty, deposits, is responsible in a major industrial country like Britain for more than 160,000 deaths each year. Although major heart surgery is becoming commonplace, with more than 28,000 bypass operations in the UK annually, it is traumatic for patients and involves a long recovery period.  
One reason for malaria to be more widespread now is that_________.

选项 A、more people have moved to malaria-infected areas
B、mosquitoes have become resistant to pesticides
C、genetically modified mosquitoes still transmit the disease
D、mosquitoes bite as many as 500 million people a year

答案B

解析 细节题。Excerpt 2最后一句说:“because of drug resistance and population changes,malaria is actually more prevalent now than it was 20 years ago.",因而可知由于蚊子对药品的抵抗力和人口的变化,现在,疟疾实际上比20年前更普遍。可见B项“蚊子对杀虫剂有抵抗力"正确。故选B。
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