1、right away意为立即、马上、即刻、毫不耽搁，侧重行动的迅速和迫切，常用于美式英语中。

例句：I need to see you, right away if possible.

我要见你，如果可能，马上。

The men are very insistent that you leave right away.

他们坚决要求你立即离开。

The King commanded that she be executed right away.

国王下令把她立即处死。

They will most likely come right away.

他们保不住马上就会来的。

2、right now意为现在、此时此刻，但也有立即、马上的含义。侧重于时间点。

例句：I'm short of cash right now.

我眼下正缺钱。

You can go right now for all I care.

你可以马上走，我才不在乎呢。

If you have a problem with that, I want you to tell me right now.

如果你有异议，我要你马上告诉我。