One man bought a lie detector and put in a corner of the room. At dinner, the father asked to son:

-What did you do at school today?

-It was all right Dad. My math exam passed very well.

Thereupon, the detector gave warning a beep and the child confessed:

I didnt go to school today. I went to movies with my friend.

Dad said angrily:

-When I was your age, I didnt know what was the cinema. I was a hard

working student.

When the detector that heard about it and again warned beeeep the

mother laughingly said:

Heres your son after all! Fathers son!

The detector began to sing at once: beeeep beeeep beeeep