回複：緊急求助！！

My understanding is that she came to USA with H-4, the visa is valid for 3 months before she entered USA (i.e., she has to use it to enter USA before it expires). Once she is in USA, her H-4 should be valid as long as her spouse's H-1B is valid. That is my understanding.
My wife came to USA after visiting China as H-4, and we did not have to renew or extend the H-4, since my H-1 was valid at that time. We got GC most recently, after a RFE for all non-immigration documents, so I believe we did not have visa problem.

Hope this helps.