64- Missing thing

A young pretty female school teacher had been telling her class about
the value of being observant and said, "Now children, look at the
clock... what does the clock have that I have too?"

One little girl stood up and said, "It has a face."

Another girl raised her hand and said, "It has hands."

"Splendid," said the teacher. "Now, what does the clock have that I
don't have?"

After a long silence, little Johnny stood up and remarked, "You ain't
got no pendulum, ma'am."