填空题

A deadly (36) outbreak swept through a small city in Zaire, Africa last spring, killing more than one hundred people. It was a terrible situation. The killer was a rare (37) that caused most victims to (38) to death. As scientists rushed to control the (39) , people in the U. S. wonder whether it could attack here. "We are foolish if we think it couldn’t come to our country. We can never be too careful when we face some disease, especially the infectious one. " say doctors. The virus can be highly infectious. If you come in (40) with a victim’s blood or other body (41) , you can get sick, too. That’s what scientists believe (42) in Zaire. The healthcare workers who treated the first (43) there soon fell ill, too. (44) . . International rescue works brought equipment to Zaire soon after the outbreak occurred. (45) . One big mystery is that no one knows where the virus comes from or where it will strike next. Some scientists say that the virus lies inactive in the ceils of some kind of plant, insect or other animal. Then it somehow finds a way to infect humans. (46) . Once they find the virus, they also hope to find ways to combat it.

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