I think John Cleese would make a brilliant teacher in this so read it with him in mind.
INT. A CLASSROOM - DAY
Just the usual classroom setup. Teacher is stood at the front, and desks are all around him. The pupils file in and sit down.
TEACHER
Now if you haven't done your homework put your hand up
A few pupils put their hands up.
TEACHER
Jenkins, why haven't you done it?
JENKINS
Dog ate it sir
TEACHER
I'm sure. Morris, what about you?
MORRIS
I was at the psychiatrists sir
TEACHER
Really? Why was that then?
MORRIS
Apparently I'm a kleptomaniac sir
TEACHER
Oh really? What about you Peters?
PETERS
Hospital sir. Lost a leg sir
TEACHER
But you just walked in here fine
PETERS
Prosthetics sir
TEACHER
A likely story. What's your excuse Horroway?
HORROWAY
Jesus visited me sir
TEACHER
This is outrageous, and not one proper excuse between you
Suddenly Morris gets up and runs off out of the room with a prosthetic leg. Peters gives chase but is hopping after him.
TEACHER
Get back here now you two!
HORROWAY
Sir, can I go to the medical room?
TEACHER
Why?
HORROWAY
My hands are bleeding sir
Horroway holds up his hands and there are circles of blood on each palm.
TEACHER
Go
Horroway leaves. Jenkins gets up and begins to walk out of the room.
TEACHER
Where do you think you're going Jenkins?
JENKINS
Need to take my dog to the vets sir