【正文】 B) dissatisfaction C) suspicion D) tolerancePassage Two Questions 16 to 20 are based on the following passage:It was once believed that being overweight was healthy, but nowadays few people subscribe to this viewpoint. While many people are fighting the battle to reduce weight, studies are being conducted concerning the appetite and how it is controlled by both emotional and biochemical factors. Some of the conclusions of these studies may give insights into how to deal with weight problems. For example, when several hundred people were asked about their eating habits in times of stress, 44 percent said they reacted to stressful situations by eating. Further investigations with both humans and animals indicated that it is not food which relieves tension but rather the act of chewing.A test in which subjects were blindfolded showed that obese people have a keener sense of taste and crave more flavorful food than nonobese people. When deprived of the variety and intensity of tastes, obese people are not satisfied and consequently eat more to fulfill this need. Blood samples taken from people after they were shown a picture of food revealed that overweight people reacted with an increase in blood insulin (胰島素), a chemical associated with appetite. This did not happen to averageweight people.In another experiment, results showed that certain people have a specific, biologically induced hunger for carbohydrates (糖類). Eating carbohydrates raises the level of serotonin( 血清素), a neurotransmitter in the brain. Enough serotonin produces a sense of satiation, and hunger for carbohydrates subsides.Exercise has been remended as an important part of a weightloss program. However, it has been found that mild exercise, such as using the stairs instead of the elevator, is better in the long run than taking on a strenuous program, such as jogging, which many people find difficult to continue over long periods of time and which also increases appetite.16. It can be inferred from the passage that _____.A) overweight people are tenseB) thin people don39。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. Lanzaro says he has a better way to stop the spread of malaria: genetically modifying mosquitoes so they are unable to carry the disease. Lanzaro and his colleagues are planning a multiyear project to produce malariaresistantmosquitoes and he thinks they can do it within five years. We can get foreign genes into mosquitoes and they go where they39。 DNA, making it impossible for those mosquitoes to transmit the parasite that causes malaria. In this way a small group of labraised mosquitoes could be released into the wild, and by interbreeding with wild mosquitoes, eventually transmit the beneficial gene to the entire population.21. One reason for malaria to be widespread now is that A). more people have moved to malariainfected areas B). mosquitoes have bee resistant to pesticides C). genetically modified mosquitoes still transmit the disease D). mosquitoes bite as many as 500 million people a year22. Lanzaro is hopeful that in a few years man can A). start to eliminate malaria B). cure parasitic blood diseases C). prevent mice from transmitting parasites D). acquire immunity against malaria23. Lanzaro is confident that scientists can block transmission of malaria to humans because A). natural mosquito populations do not change B). scientists have succeeded with birds and mice C). foreign genes always go where they are required D). labraised mosquitoes will not be resistant to drugs24. What is the most difficult part of Lanzaro39。keywinnerdesireandwhichbedesireandyouwehopeisaverageaboutbutoutandwin,beaction.canhelpwe 34. ________Competitionmotivator.useexcusethosetoasthey39。thetodealistakingsothatthem,drainedmighttoselfrespectmitmenttalents.necessarythingmostthatson