回复：中国到美国纯旅游签证有没有？

my uncle and aunt just came here last September on tourist visa. all I provided to them was a invitation letter and a copy of my green card, no finacial support or any other documents. they both have been retired for several years, and has been to some southeast acian countries and Korea. They provided their own finacial support documents from China. They also paid for their own airline tickets. They are allowed to stay for six months.