The vaccine was significantly more effective … if they had not b

来源: ephd 于 2015-12-01 14:18:31 [] [博客] [旧帖] [给我悄悄话] 阅读数 : (258 bytes)
本帖于 2015-12-01 14:19:42 时间, 由普通用户 ephd 编辑

The vaccine was significantly more effective … if they had not been vaccinated in the previous five years.

这句话还不能说明问题吗？ 应该好好想想是不是要年年都打疫苗，或者应该每5年打一次？

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