回复：Two questions regarding H-1 and AP

Is it OK to go back to apply for H-1 while H-1 is pending for renewal?
--yes, but 可能要等到批准后才给你visa

Everyone says that one can keep H-1 status after using AP if he doesn't change the current job. My employer has a definite asnwer to that --> H-1 will be invalid once AP is used.
--both are right, using AP you enter AOS/H1 dual status, 不在是纯的H1,也不是纯的AOS

My question is how the employer knows whether or not I use AP.
--严格讲,你不show给他,雇主不回知道

The only evidence is the stamp on the I-94, right? Do I have to give the I-94 copy to the employer after coming back to work?
--没有政策上必然要求,如果雇主要求,也将是个案