Little Johnny was sitting in class one day. All of the sudden, he needed to go to the bathroom. He yelled out, "Miss Jones, I need to take a piss!!" 来自幽默学英语网http://www.linkstom.cn/humor/
The teacher replied, "Now, Johnny, that is NOT the proper word to use in this situation. The correct word you want to use is 'urinate.' Please use the word 'urinate' in a sentence correctly, and I will allow you to go." 
Little Johnny thinks for a bit, then says, "You're an eight, but if you would let me go piss, you'd be a ten!!!"