练习：

　　1.Paragraph 2 _________.

　　2.Paragraph 3 _________.

　　3.Paragraph 5 _________.

　　4.Paragraph 6 _________.

　　A　Reasons for Excluding Masks from the Self-protection List

　　B　Effort to Stop Flu from Spreading

　　C　When to Use Face Masks

　　D　Guidelines on Mask Use

　　E　Warnings from the CDC

　　F　Danger of Infection through Germy Hands and Masks

　　5.The scientists are trying to find out if masks may or may not _________.

　　6.The CDC is afraid that the public may _________.

　　7.The public will not know the answer about masks until scientists _________.

　　8.We can infer from the passage that the US authorities _________.

　　A　overuse face masks

　　B　deal with the mask problem seriously

　　C　rub their faces and noses in the subway

　　D　protest against the mask guidelines

　　E　help protect people from being attacked by a flu

　　F　announce the results of their mask research
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