@bidens_diaper @J_D_Klein @HalCranmer CDC cites three studies for masks working in schools. You may not agree with this evidence, or disagree it is representative, but that is far different from saying "no evidence whatsover", which simply isn't the case.
https://www.cdc.gov/media/rele...
@bidens_Dipper@J_D_Klein@HalCranmer疾病预防控制中心引用了三项关于在学校工作的口罩的研究。你可能不同意这个证据，或者不同意它是有代表性的，但这与说“没有证据”是完全不同的，事实并非如此。
https://www.cdc.gov/media/rele...