My Sister Lied to Her Parents, But They Knew It

Do you know anything about lying? We were taught from childhood that lying is bad, that you can not lie, you should always tell only the truth. But is it always right, and what does it mean to lie for good? I didn't understand that phrase very well until I came across it myself. In general, we will talk about my sister. Don't jump to conclusions, just listen to me until the end...