填空题

It is as risky as the natural evolution of the virus that the scientists breed contagiousness into H5N1 to see if it is likely to happen.

【参考答案】

Y

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热门试题

填空题

Scientists think that we should blame the virus of flu all on wild birds.

填空题

H5N1 could evolve into a potential pandemic that way, or by recombining with human flu.