详细解释:ad. 一次, 曾经, 一旦
conj. 一旦, 一经
n. 一次
a. 从前的
相关词组:
once or twice
not once
all at once
at once
at once...and...
more than once
once more
once and again
once and away
once and for all
once in a way
once in a while
once too often
just for once
once upon a time
once a week
词意辨析：
once, as soon as两者均为从属连词，引导时间状语从句，都表示主句的动作紧跟在从句的动作之后发生。
once: 除表时间外，还表示条件，一般译作“一旦......就......”。once he makes up his mind，he’ll never give it up.
他一旦下定决心，就决不会放弃（本句不可用as soon as）。
as soon as: 强调的只是时间，译作“刚......就......”或“一......就......”。as soon as i get to beijing，i’ll write to you.
我一到北京就写信给你。英语解释：
副词 once:
on one occasion同义词：one time, in one case