Liu Ming is my chemistry’ teacher. He is an ordinary-looking little man with thick glasses, but he has a strange way of making his classes lively and interesting.

　　I remembered his first lesson. He put three bottles on the desk. One was filled with kerosene, one with castor oil, and one with vinegar. And he said "Now watch carefully. Pay attention to everything that I do." He held up one of his fingers and dipped it into the cup after he mixed the three kinds of liquid in a big cup together.

　　A few seconds later, he took his finger out, put it in his mouth and sucked it. "How delicious! You must do everything that I do." said he. And then we did it like him. lmmediately we made a face. The mixture tasted horrible.

　　It was first chemistry lesson. I never forget it.