Can anybody share your suggestion or opinion.

I am from Jiangsu, China, stayed in US for 3 months in Spring 2005, and then landed in Canada (my Canada immigrant visa was issued in Sydney,not in US)become Canada PR and now live in Canada already for one and half year, but I like and plan to live in US and want to go there,If I can apply and then get US green card there in the future, I hesitate and want to know if I still should keep Canada PR or not once I get US green card, if I want to keep Canadian PR, I need live in Canada at least 2 years within 5 years or swear allegiance to Canada to become a citizen after living in Canada 3 years(but I don't like to do this because I cannot be allegiant to Canada since I don't want to live in this country long time or all my life in my heart though I think it still a good country for some people and some canadians are very kind and helpful to me,I am grateful to them,I do not want to hurt them and their country which helped me before).Can anybody give me some suggestion or share your opinion?Thanks a lot.