I'm going to play Uno instead of work while the teacher is gone.
Why are you going to play Uno instead of work?
I don't want to work. Wouldn't you do the same if you were me?
It's normal to slack off when the teacher leaves the room, but you shouldn't slack off too much. If you don't do your work at all, then your teacher will be disappointed and she may even punish you.
Why? I'm just playing Uno...
It is wrong to slack off at school. You should try to learn because you need good grades to get into a good school to find a job that pays more then minimum wage.