2aListen to Mary continue her story. Number the pictures［1-4］in the correct order.
Boy: So then what did you do, Mary?
Mary: Well, I ran home to get my backpack. But when I got home, I realized I had left my keys in the backpack.
Boy: You're kidding!
Mary: So I ran back to school without my keys or my backpack. But by the time I got back to school, the bell had rung.
Boy: Oh, no!
Mary: And by the time I walked into class, the teacher had started teaching already. She asked for our homework, but of course I didn't have it.
