user-friendly

a.容易操作的，好用的

urinate, urine, urn, us, USA, usable, USAF, usage, use, use up, used, used to, used to do, useful, usefully, usefulness, useless, uselessly, uselessness, user, usher, usherette, USN, USS, USSR, usual, usually, usurer, usurp, usurpation, usurper, usury, Utah, utensil, uterine, uterus, utilise, utilitarian, utility, utility room,