回复：请PIJIANG和各位高手Confirm

1。我去年刚延期了H1B，拿到了I-797 Approval Notice，但今年年初用了AP入境，所以我的H1B Status就不存在了，那么我的H4也就不可以去美国使领馆签H4签证了？
-Are you still working for your original employer who sponsored you H1? If yes, you still can reinstate your H1 status by extension or going out of US to get a h1 visa.

2。如果我没有H1B Status了，手中的I-797 Approval Notice 还有用吗？可以用来申请H1B签证吗？移民局备忘录里只说了Parolee可以extend H1B STATUS，没说可以去申请VISA。
-Of course, you can use it for h1 visa application as long as the I-94 with this notice has not expires yet.

3。如果我可以申请H1B VISA，并用签证回美国，H4去签证就没问题了吧？还需要在美国先申请个身份转延（I-539）吗（H4在Parolee之前是F1）？
-The original H4 holder needs to extend h4 or get H4 visa if he/she wants to reinstate the H4 status (do the same thing as h1 holder).