prescriptive
/prɪˈskrɪptɪv; prɪ`skrɪptɪv/ adj
(fml 文)1
(a) making rules or giving orders or directions 规定的; 指定的; 规范的
prescriptive teaching methods 规定的教学法.
(b) (grammar) telling people how they ought to use a language （在指导语言运用方面）规定性的, 规范性的
a prescriptive grammar of the English language 英语规范语法. Cf 参看 descriptive 2.
2 made legal or acceptable by long-standing custom 因长期使用而合法或认可的; 约定俗成的
prescriptive rights 因时效而获得的权利.