Step-by-step explanation:
2.Since I was a child- so for fifteen years
3. How long has your father worked in the bank?
4.For five years
5.How long have you had the same hairstyle?
6.Since I was about six
7.How long have you known your best friend?
8.For three years
9.How long is your class, study and English?
10.Since we were at primary school