What do you see?

Teacher: Why did you laught?
Student: I saw a strap of your bra
Teacher: Get out. No class for you for a week.

Another student laughts.
Teacher: Why did you laught?
Student: I saw both straps
Teacher: Get out. No class for you for a month.

She bends down to pick a chalk.
All of other students went out
Teacher: Why are you all going out?
Students: with what we saw, we think our school days are over...