at

prep.在…时；在…中；在…方面；向，朝

astrolabe, astrologer, astrological, astrology, astronaut, astronautics, astronomer, astronomical, astronomy, astrophysics, astute, astutely, astuteness, asunder, Aswan Dam, asylum, asymmetric, asymmetrical, asymmetry, asynchronous, at (the) best, at (the) worst, at a disadvantage, at a good pace, at a guess, at a loss, at a speed of, at a stretch, at a time, at a...price, at all, at all costs, at all events, at all risks, at all times, at any cost, at any rate, at any time, at best, at ease,