1)The English language is now the first language of about 350 million people, the native language of 12 nations and the official language of more than 33 nations. It means that one of seven people in the world speaks English.So...I think this is a big reason for study this language.In future I will have a lot of communication with different people from different countries and I should know common language.
2)Это сам,я не знаю что тебе нравится)
3)Тоже самое
4)I can use my english for reading foreign websites and literature.For speaking with people from different countries.
5)In my opinion,practicing of the speaking with native speakers is the most helpful development of my english.And also is helpful reading of english books.And of course watching of films and сartoons in english.