My son will be going to China to participate in 2 different study progrsms with 2 different letters of invitation. He will have to reapply for the 2nd visa while in China (or leave to go to Hong Kong and reenter). We have the 1st letter of invitation which states it is for 90 days beginning in early June. We bought his round trip ticket with a return date in December 2010 since that is when the second program will end. Will anyone question him about the return date on his ticket (will they even notice this?) at customs when he arrives in China? He will have the second letter of invitation sent to his address in Beijing where he will be studying and will be arriving sometime during the summer. I am wondering if there will be a problem for him when he arrives in China with a round trip ticket that will be after his present visa expires. Thank you for your help.