Mutations in the virus mean that last year's vaccine probably won't protect against this year's flu variety.

VOA: standard.2010.07.21

I didn't have the flu at the time but I became violently ill.

我那会并没得流感，但却病的很重。

耶鲁公开课 - 心理学导论课程节选

I didn't have the flu at the time but I became violently ill.

我那会并没得流感，但却病的很重。

耶鲁公开课 - 心理学导论课程节选