Dear (điền tên vô)! 

Hi! How are you? How is your family? Recently I heard that your English score is very low. I know you don't like to study and especially English but it's very important. You will probably ask why right? OK! English is a global language. Once you learn it, you can easily communicate with people and can quickly adjust to your new environment while traveling abroad. Now you understand why learning English is so important, right? So let's try to learn!

Hope you are well!

Your best friend, (điền tên zô)!

bài của mình, bạn tham khảo nhé [không chép mạng]:
Dear [điền tên người bạn],

i received your sweet letter on time. you wanted to know why learning english is important, now i'll tell you why.

english is important in numerous ways, it is a global language that is spoken by people all over the world. if we wish to communicate with people in other countries, we must know english. all international seminars and discussions are held in english. it is also required for further education and a good job. i hope you now can realize the importance of learning english and read it well.

your friend,
[tên của bạn]