@NealC: Thanks for your feedback.
I used some words were wrong and I know this. You know, I am not a native speaker. And I am trying to reduce anything that I made mistakes. So I hope you understand it.
@Aurelio: it's really useful when I read your comment. I know, I am not keen on learning English when I begin. My attitude has impact negavetive on learning. But now I have changed it and I am trying to practice Elnglish everyday. I spent about 5-7 hours a day to learn English by myself. I listen VOA special English, read books written by English and especially, I read a book namely Introductory Econometrics by English that I am interesting in the subject. In addition, I intend to study abroad and my English skills are necessary that is really my motivation.
Wishing you a good health and happiness.
Thank you so much.