The W. H. O. has an influenza warning system in which phase six means that a pandemic is taking place.

世卫组织拥有一套流感预警机制，六级意味着流感病毒的大规模流行。

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The W. H. O. has an influenza warning system in which phase six means that a pandemic is taking place.

世卫组织拥有一套流感预警机制，六级意味着流感病毒的大规模流行。

youdao