[希望对你有帮助]

I am learning English now,because I want to study my master courses in America.

I am learning English because I am planning to to take a masters course in the USA.

[Saying USA, or US, makes it clear you mean that particular country]

I like to make friends with people from english country.

Therefore, I would like to make friends with people from English-speaking countries.

I am a native chinese.I enjoy books,photography and drinks.

I am a Chinese national, and I enjoy reading, photography, and going to bars.

[Sounds a bit strange to say "native Chinese"; "native American" is a set ethnicity meaning people who were there before the white people arrived. Also, it's not really correct grammar to say "I am a Chinese", so you should put a noun on the end like "person", "girl", etc.]