因为在国内有至今还未处理好的棘手事情，所以一直没有登陆美国，请问老师，
-Check the immigration visa to see whether it expires or not (normally it is valid for 6 months). If not, you can enter US using that visa. If it expired, you can not use it any more.
If you enter US with this valid immigration visa, you will get the lawful permanent residency/status (green card)immediately at the port of entry. The CBP officer will endore your immigration visa (put green card stamp) on your passport and you can use this stamp for the international travel and work. of course, USCIS will send you the physcial green card to you in about one month.
我可否现在进入美国，提交绿卡申请，小住2个礼拜，然后回中国，等待绿卡批准，请朋友把绿卡寄给我？等我处理好国内的事情再用绿卡回美国？
-Not need 提交any绿卡申请 (see above answer). You also do not need 朋友把绿卡寄给you because you can use the green card stamp to come back.
