父母有绿卡，去年十月底回中国，原计划三月底回美，正好五个月。 现在因为疫情， 航班取消。 父母倒也不急着回来。 如果想到今年年底再看情况，请问是否需要申请什么手续？ 谢谢您
-If your parents come back to US before their stay in China reaches one year, then they just use the green card to reenter US, notthing else is needed to do. But if they cannot return US after October due to the covid-19, their green card will be void. Thus, they may have to apply for SB-1 and this is a very cost processing in time, money and risk.
