Required
来自Big Physics
late Middle English: from Old French requere, from Latin requirere, from re- (expressing intensive force) + quaerere ‘seek’.
etymonline
required (adj.)
"that must be done as a condition," c. 1600, past-participle adjective from require (v.). Required reading, that which must be read to attain an understanding of a subject, is attested from 1881.
