prolonged
adjective uk/prəˈlɒŋd/ us/prəˈlɑːŋd/
C1 延续很久的，长期的
continuing for a long time
Prolonged use of the drug is known to have harmful side-effects. 据了解，长期服用此药会产生对人体有害的副作用。
Synonyms: drawn-outextendedlengthylong (TIME)protracted