at a time，at one time 和at the time有什么区别

at a time，at one time 和at the time区别及例句：

at a time :一次；每次；在某时

Let your listener answer one question at a time.

让你拦仔迟的听众一次回答一个问题

at one time :曾经，一度；同时(大多时候可以同at a time 替换简李）

All showed signs that,at one time,they had been active.

所有戚悄迹象表明，它们曾一度活跃过

at the time ：在那时，那时候

At the time,printing itself was not a new idea.

在当时，印刷术本身并不能算是一个新想法

at all times：一直；始终

Please pay attention to them at all times.

请随时注意遵守这些规则。

at times：有时，偶尔，不时

She was a fun person to be with at times. 

与她相处有时很开心。