VOA慢速英语:大学生填补了代课教师的需求

substitute – n. a person or thing that takes the place of someone or something else

awesome – adj. extremely good

dean – n. a person who is in charge of one of the parts of a university

alternative – adj. offering or expressing a choice

quarantine – n. the period of time during which a person or animal that has a disease or that might have a disease is kept away from others to prevent the disease from spreading