VOA慢速英语:美国教师离职 学校急寻替代者

exposed – adj. not protected or covered

graduate – adj. of or relating to a course of studies taken at a college or university after earning a bachelor's degree or other first degree

infrastructure – n. the basic equipment and structures such as roads and bridges that are needed for a country, region, or organization to function properly

quarantine – v. to keep (a person or animal) away from others to prevent a disease from spreading