A. smallpox Black Death C. the 1918 influenza pandemic D. COVID-19
A. 4 B. 6 C. 7 D. 5
A. contact tracing B. isolation C. mitigation D. vaccination
A. frequent hand washing B. wearing a surgical mask C. yearly vaccinations D. plenty of rest and taking medication
A. public health necessity B. reasonable and effective means C. trust and transparency D. distributive justice
A. 对 B. 错