需要回中国或者加拿大，还是就在美国面试就可以了。
-You can either file I-485 within US to get your green card or go to Canada (not China) to apply for the immigrant visa to come back to become a green card holder.
还有，姐姐在美国20多年，一直有高薪工作，但就从前两个月开始，没上班了，因为小孩十一年级了，她想这段时间好好照顾小孩。我记得是不是我姐应该要有工作，才可以帮我申请移民？
-Not necessary. If her spouse has enough income, her spouse can provide the support by filing I-864A to together with her I-864 to sponsor your immigration.
然后前两天看资料，发现我只收到过所谓的P1 number, 没有P2 的case number, 但我用P1 number, 能在移民局网站上查到我的信息，这样可以吗？问题太多了，谢谢老师
