upgrade

v.提高等级

up, up and doing, up and down, up in arms, up to, up to date, up to time, up-, up-and-coming, up-country, up-end, up-market, up-to-date, up-to-the-minute, upbeat, upbraid, upbringing, upcreep, update, updating, upheaval, uphill, uphold, upholder, upholster, upholsterer, upholstery, UPI, upkeep, upland, uplift, upon, upper, upper case, upper-cut, uppermost, uppish, upraise, upright, upright piano (also upright),