unable

a.不能的，不会的；无能为力的

ultraviolet, ululate, ululation, Ulyanovsk, umber, umbilical, umbilical cord, umbilicus, umbra, umbrage, umbrella, umlaut, umpire, umpteen, umpteenth, un, un-, un-American, unabashed, unabated, unabridged, unacceptable, unacceptably, unaccommodating, unaccompanied, unaccountable, unaccountably, unaccounted, unaccustomed, unacknowledged, unadopted, unadulterated, unaffected, unaffordable, unafraid, unaided, unalloyed, unalterable, unaltered, unambiguous,