For example, if you have myasthenia gravis, you may notice that during a meal, your jaw muscles become tired and weak, interfering with your ability to chew food. After you have rested for a little while, the muscles may become strong again, allowing you to resume eating.
Reentry Permits. If you hold a green card and know in advance that you must be outside the United States for more than one year, it's worth applying to USCIS for a reentry permit. This lets you to stay away for up to two years. See â Reentry Permits: Preparing Green Card Holders for Long Absences from the U.S. â.
I have read from many sources thru internet and the answer is one year. Now, i have been in the situation wheares I stay outside the US. every 6 months and when my 6 month is up, I would fly back to the US. so my green card would be valid. I have done this about 3 times over the past 2 years and I will wait for one year this time before i go back there this March.