Đáp án + Giải thích bước giải:

* Bài tự làm, b tham khảo ^^

From: ABC
Address: ABC city
To: CBA
Dear CBA,
It appears as though you have some difficulty when remain at my level. Be that as it may, you can definitely relax, I'll help you. If you have any desire to get the keys, go to the first floor and an oversee will give you the keys. Simply tell her the level and floor. I'll give you a card so you can utilize the lift. There's a general store close to my home. Go straight then turn left, and you'll see that general store.
In the event that you really want assistance, kindly send email to me.
Your companion,
ABC