other people's kids.....I'll tell you...

student: I'm missing assignments.
me: yep. *grades other people's stuff*
student: Why?
me: 'Cause you didn't turn them in, or if you did, your name wasn't on them.
student: I had to turn those in?
me: *stops grading other people's stuff, gives him a look... very very slowly...* Yes, you have to turn the homework in.
student: Oh, I didn't know that.
me: *thinks, "how the heck would I give you points for it otherwise?"* Yeah, you have to turn it in.
student: But I did it.
me: So bring it in next time.
student: Oh, you can't tell I did it?
me: *the homework is printed out and then filled out by hand, so uh... no* No, you need to turn it in for credit.
student: Oh, okay.

*head desk*