VOA慢速英语:报告称有的人是新冠病毒的无症状感染者

symptom – n. an indicator that one is sick

contagious – adj. an illness that can be passed from one person to another

complicate – v. making more difficult or complex

positive – adj. an outcome that indicates an affirmative

swab – n. a small piece of cotton or clothe

cough – n. sudden expiration from the throat