回複：急問, H1B 延期辦的過晚,怎麽維持中間時間的身份?

I don't think it will take 50 days to get the receipt notice. Once you send your application, it will take less than a week to receive the notice. That is only based upon my own experience dealing with NSC not CSC. I am not so sure if you have to receive the exention approval to continue your work. Good luck.