问题 选择题

今年3月底,在我国几个省市发现新型H7N9禽流感病例.专家提醒,食用禽产品时要充分煮熟.从传染病的预防来看,该措施属于(  )

A.控制传染源

B.保护易感者

C.切断传播途径

D.消除病原体

答案

甲型H7N9传染病属于呼吸道传染病,传播的途径是通过空气和飞沫传播.传染病流行的三个基本环节是:传染源、传播途径和易感人群.传染源:能够散播病原体的人或动物.传播途径:病原体离开传染源到达健康人所经过的途径叫传播途径,如空气传播、饮食传播、生物媒介传播等.易感人群:对某种传染病缺乏免疫力而容易感染该病的人群叫易感人群.传染病的预防措施是控制传染源、切断传播途径、保护易感人群;因此,专家提醒,食用禽产品时要充分煮熟.从传染病的预防来看,该措施属于切断传播途径.

故选:C.

论述题
单项选择题

If there is one thing scientists have to hear, it is that the game is over. Raised on the belief of an endless voyage of discovery, they recoil from the suggestion that most of the best things have already been located. If they have, today’s scientists can hope to contribute no more than a few grace notes to the symphony of science.

A book to be published in Britain this week, The End of Science, argues persuasively that this is the case. Its author, John Horgan, is a senior writer for Scientific American magazine, who has interviewed many of today’s leading scientists and science philosophers. The shock of realizing that science might be over came to him, he says, when he was talking to Oxford mathematician and physicist Sir Roger Penrose.

The End of Science provoked a wave of denunciation in the United States last year. "The reaction has been one of complete shock and disbelief, "Mr. Horgan says.

The real question is whether any remaining unsolved problems, of which there are plenty, lend themselves to universal solutions. If they do not, then the focus of scientific discovery is already narrowing. Since the triumphs of the 1960s—the genetic code, plate tectonics, and the microwave background radiation that went a long way towards proving the Big Bang—genuine scientific revolutions have been scarce. More scientists are now alive, spending more money on research, that ever. Yet most of the great discoveries of the 19th and 20th centuries were made before the appearance of state sponsorship, when the scientific enterprise was a fraction of its present size.

Were the scientists who made these discoveries brighter than today’s That seems unlikely. A far more reasonable explanation is that fundamental science has already entered a period of diminished returns. "Look, don’t get me wrong," says Mr Horgan. "There are lots of important things still to study, and applied science and engineering can go on for ever. I hope we get a cure for cancer, and for mental disease, though there are few real signs of progress.\

The best title of this passage can be()

A. Great Scientific Discoveries Will Never Be Possible

B. The Harsh Challenge Has to Be Met by Modern Scientists

C. The State Sponsorship and Scientific Enterprise Are All in Vain

D. The Chance for Great Scientific Discoveries Becomes Scarce