on the spots/at once/ right now/right away的区别

on the spots/at once/ right now/right away的区别 at the moment , at once,right now,right away区别 at once ,right now,right away和now的区别 at once right now right away at the moment 区别、比如用在哪个时态 我想知道right now ,right away ,at the moment 和 at once 他们四个的用法 right away 与 at once的区别 right away ,at once, immediately 的区别? at once &right away区别 right now 和 at once 的区别? 一些英语单词解释right away、at once、 right now、in a minute 、at the mo right away=at once=right now? right away 和right now的区别?