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Harper Green School on Twitter: "The Government has issued temporary guidance that ALL secondary school students must wear face masks at all times including in classrooms when returning to school, unless exempt.
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How to Put on and Remove a Face Mask - Disease Prevention and Control, San Francisco Department of Public Health
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Medical Face Mask Icon Coronavirus Vector Illustration Stock Illustration - Download Image Now - iStock
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Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021 | MMWR
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