urgency

n.紧急

upwards, upwards of, upwind, uranium, urban, urbane, urbanely, urbanity, urbanization, urbanisation, urbanize, urbanize, urbanise, urchin, Urdu, urea, ureter, urethra, urge, urge sb to do, urge sb. on, urged, urgent, urgently, uric, urinal, urinary, urinate, urine, urn, us, USA, usable, USAF, usage, use, use up, used, used to, used to do, useful, usefully,