as soon as与as well as的区别

as soon as与as well as的区别是什么？
at once与as soon as的区别？

as soon as

1. 一…(就…)2. 如…那么早(或快)，如…一般早(或快）3. 一…(就…)4. 如…那么早(或快)

eg.Tell me as soon as she arrives.

as well as

1. 除…之外(也)，同…一样(也)，和，也，还2. 与…一样(程度)3. 既…又… 4. 与…相同；不亚于…5. 此外，也

at once 和 as soon as
at once:立刻，马上，同时，一起
eg. He stopped playing the piano at once.
他立刻停止了弹钢琴。