A blonde gets a job as a teacher

 She notices a boy in the field standing alone, while all the other kids are running around having fun.

She takes pity on him and decides to speak to him.

'You ok?' she says.

'Yes.' he says.

'You can go and play with the other kids you know' she says.

'It's best I stay here.' he says.

'Why?' says the blonde.

The boy says: "Because I'm the bloody goal keeper"