Everyday an ESL teacher was seen coming out of the restroom with a marker. in the restroom were expressions and graffiti written on the walls. It was very bad. Finally, the Director of the school called the teacher into the office and told the teacher that it was terrible of him to write those things on the walls. The teacher said that he was not the one writing those things. all that the teacher did was to correct the grammar.
teacher: " Nick, what is the past participle of the verb to ring?" Nick: "what do you think it is, Sir?" teacher: " I don't think, I KNOW!" Nick: " I don't think I know either, Sir!"