1) I desire an immediate answer of yours.
我请您立即回信。
2) I beg you will answer by return of post.
我请您立即回复。
3) Please give me an immediate reply.
请立即答复我。
4) It took less than no time to write a reply.
立即写好了回信.
5) Return of Post
请即回示
6) return of post
请即回电
补充资料：立即
立刻：接到命令，～出发。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条