at night

天黑时；在夜里

at any rate, at any time, at best, at ease, at first, at first sight, at full speed, at full tilt, at hand, at heart, at home, at intervals, at large, at last, at least, at leisure, at length, at longest, at lowest, at most, at no time, at odds with, at once, at one time, at one's best, at other times, at peace, at present, at random, at regular intervals, at sb's disposal, at sb.'s heels, at sea, at sight of, at stake, at table, at that, at that rate, at the back of, at the beginning of,