有效期

duration of validity;time of efficacy; term(or period) of validity
在签证～内和入出境有效次数内，他们可以自由进出该国，而无须履行其他手续。They may come to or leave the country freely within the duration of the validity of the visa and the number of entry/exit granted without having to go through other procedures./本议定书自双方签字时起生效，～为8年，除非经双方同意延长。This Protocol shall enter into force upon signature by both Parties and remain in force for eight years,unless extended by mutual agreement./本护照前往世界各国，自发照之日起～5年。This passport is valid for travel to all countries in the world within a period of five years from the date of issue./在签证～内within the period of validity of the visa/延长合同的～prolong (or extend) the contract’s period of validity/本护照～延长至…The validity of this passport is extended to…/～为12个月valid for 12 months/药品的～expiry(or expiration)date of medicine