find a notary, let him declare that you are single on the paper about 25$. go to quebec notary office at square victoria ,stamp it about 15$. mail to the china embassy let them give you a verification cost about 30$ to 50$.
I have already canceled my hukou when i leaved China, but I am pretty sure that I can get marry certificate with my GF in China(We decide to get marry in my hometowm in that I can get marry certificate there without my Hukou in Guangzhou.
Is it needed for me to apply for a single status certificate before I leaving Canada for marry.