"he answered immediately"
"found an answer straightaway"
"an official accused of dishonesty should be suspended forthwith"
"Come here now!"
"he took three cookies at a time"
1.
1. 马上:- my path is clear. 我的道路通畅 | -atonce. 马上 | - of course. 当然
2. 立刻:at no time 从不,决不 |atonce立刻 |at one time 同时,曾经,从前曾
3. 立刻,马上:at one time 以前,曾经 |atonce 立刻,马上 |at night 在夜里,在晚上
4. 同时:at least 至少 |atonce 同时 |at the most 至多,顶多