canadian teacher going to china

Hello,

I am a Canadian teacher and my Alien card expires in 1 month but I will be renewing it as I am staying another year, however I am hoping to go to China in 2 weeks for a short visit. Is it possible to get the visa without 6 months left on my alien card? Do I have any options? I read somewhere that if I am in China for 3 days or less that I wouldn't need a VISA. Can you clarify for me

Thanks,