听起似乎差,尤其文,都尽快意思.区别于:as fast as 表示作尽能快,说作本身,比:he is running as fast as he can 用快速度往跑.as soon as 指尽快做作,比较:he runs there as soon as possible,旦(跑)马往跑.候差意思,:reply me as soon as possible(或as fast as possible)尽快给我复 总说,fast 比较具体,soon 比较抽象 希望能帮助