at the regulation speed
規定の速度で
at the request of ...
…の要請で
at the sight [the sound, the thought] of ...
…を見て[聞いて,考えて]
at the start of the winter
初冬に
at [on] the stroke of midnight
深夜0時ちょうどに
at [on] the stroke of twelve
12時が鳴ると;12時きっかりに
at the time of expiration
任期満了のときに
at the top of a table
上座に
at the top of one's lungs
声を張り上げて,声を限りに
at the top of one's speed
全速力で