The teacher asks the class: “Where do apples grow?”
Smart Samantha answers: “On apple trees. “
The teacher asks the class: “Where do pears grow?”
Clever James answers: “On pear trees. “
The teacher asks the class: “Where do dates grow?”
The class is silent. Little Johnny raises his hand and says: “On calendars?”
This joke is included in the Black Book of Jokes. You can order it from here.