Learning English through Jokes

It was the first day of Biology for a group of teenagers. The
professor had arranged a short demonstration for the class.

He took a worm and dropped it into a glass of water. The worm
wriggled about in the water.

Then he took a second worm and dropped it into a glass of alcohol.
The worm immediately died.

The professor asked the students if anyone knew what the point of
the demonstration was.

A boy raised his hand and said, "You're showing us that if we drink
alcohol, we won't have worms."