The sound of a mosquito can mean trouble in many parts of the world. The bite of the mosquito can be deadly. The insects carry serious diseases like malaria. It is estimated that almost 630,000 people died from malaria and malaria-related causes in 2012, and most of these cases were in African countries.
In the United States, a group of California scientists is working to develop a more effective and less costly substance(物质)to protect people from mosquitoes. The researchers are investigating the sense of smell in mosquitoes. They found the insects use the same receptor(感受器)for identifying carbon dioxide in human breath as they do for the smell of our skin. Anandasankar Ray, who is leading the investigation, says scientists tested more than a million chemical compounds(化合物)until they found a substance called Ethyl pyruvate. He says Ethyl pyruvate makes the mosquitoes' receptor inactive. ”When we apply Ethyl pyruvate to a human arm and offer it to hungry mosquitoes in a cage, very few of the mosquitoes are attracted to the human arm because only a few of them are able to smell it out,” said Ray.
Genevieve Tauxe, a member of the research team, says it was not easy to find the neurons (神经元)of nose cells that recognise both the smell of human breath and skin. "With the device used to examine mosquitoes, we are able to insert a very small electrode(电极)into the part of the mosquitoes' nose, where its smelling neurons are and where the smell is happening," said Tauxe.
Anandasankar Ray says a product based on Ethyl pyruvate may cost less to produce than DEFT，the most effective chemical treatment now in use. He says DEFT is too costly for most people who live in areas affected by malaria.
“Perhaps by finding smells that can attack other target receptors, we will be able to improve upon DEFT and finally have the next generation of insect behavior control products," said Ray.
1:The best title for the passage is most probably __.
A.Scientists Find New Substance to Fight Mosquitoes
B.A New Generation of DEET Has Been Developed to Kill Mosquitoes
C.Malaria一a Serious Disease Causing 630,000 Deaths
D.Ethyl Pyruvate一an Insect Behavior Control Product
2:According to the passage, Ethyl Pyruvate can__.
A.kill the mosquitoes' smelling neurons
B.cause the mosquitoes to lose their sense of smell
C.result in the inactiveness of the mosquitoes' receptor
D.make the mosquitoes uninterested in human breath and skin smell
3:Through the passage, the writer aims to__.
A.inform readers of the new development in fighting mosquitoes
B.praise the achievements made in the battle against malaria
C.introduce a cheaper product in fighting mosquitoes
D.tell the differences between Ethyl Pyruvate and DEET
4:This passage most probably appears in__.
A.the column of newspaper ads
B.the health column of a magazine
C.a textbook of medical schools
D.a collection of doctors' essays
1:A。文章标题类题。通过文章最后一段we will be able to improve upon DEFT and finally have the next generation of insect behavior control products可知DEFT只是一种杀蚊药，而文章主要讲科学家研制出一种新的效果明显花费低的药品。侧重点在于新的药品。故选A。
2:C。细节题。通过第二段He says Ethyl Pyruvate makes the mosquitoes' receptor inactive. 可知Ethyl Pyruvate会使蚊子的感受器迟钝。故选C。