Ключевые слова: 21, 21 only, access, accessibility, accessible, admission, admit, admittance, adult, age, aged, attention, badge, ban, black, clean, condition, corroded, distress, entry, explicit, flat, forbidden, imprint, law, legal, limitation, mature, message, only, pass, permission, phrase, prohibited, prohibition, restrict, restricted, restriction, rosette, rubber, seal, sharp, stamp, stricture, taboo, texture, textured, twenty one,