You are having a girls talk with your one and only sister- I mean.. step sister. Even tho she's just your step sister, you've been always assumed that she's your sister. In the middle of the conversation, your boy bestfriend calls you to ask about a school project

After staring at you talking on the phone for a few minutes, she knows well it's a boy. She asked you "Who is that boy, your boyfriend, hmm? Why didn't you tell me about it, huh?"