how to change my Chinglish into pure English?

I agree with one of the earlier comments...you "should not HAVE to change" - be proud of your culture. The Chinese have some wonderful qualities! Maybe you should find more understanding friends... Learning another language is a very hard thing to do! You need to remember that! You have succeeded in learning more than one language - that is amazing! Can your laughing buddies say the same thing? English is my given language and I have trouble with it at times...and we all think in very different ways. Our "thinking" and "expressing" stems from our individual background, experiences, culture, and who knows - maybe even heredity. I encourage you to keep up the GREAT work! Be proud of your accomplishments AND your culture! Do you best and just BE YOU! :-)

I don't believe you should have to change. Being proud of your culture is an honorable thing. Do your best at learning new things but hold firm to what makes you who you are. I hope your friends are teasingly laughing at you and not being mean.

sorry to hear that you do have such kind of friends. why the heck will they laugh on you, on how you speak English?.. anyway, good to hear that you are really studying on how to speak English fluently. consider that as an achievement! not all Chinese knows how to speak English or chinglish, as you said. try to read English books like novels, magazines, or anything with English contents. read it loud and it will help you little by little to speak Fluently. listen also to English songs and try to follow it. it's a better practice. don't worry, lots of us has a problem just like yours. we just need to practice.