回複：疑難485旅行問題,請求專家小白兔,PJIANG回答

If you have time to get AP, get AP.
If you don't and I-485 approved when you are in Canada, 1. CBP allows you to come back using H4 I-94 without data entry (like doing a new admission), no problem. 2. if CBP wants to do a new admission, or if back from places other than north america (such as China) and thus must do a new admission. You must ask for deferred inspection, because you cannot officially be admitted in H1 while having LPR. Do ask deferred inspection to avoid bigger trouble in this case.