学进去

When Mary Smith was ____, she wanted to be a teacher. ____ she liked children.

When she was twenty, she began teaching in a small school. She was a good teacher, and she ____ a lot with the children in her class. They ____ her teaching.

One day ____ of the girls in her class said to her, “Miss Smith, ____ does a man's hair become grey before his beard（胡子）does?”

Mary laughed and answered, “I don't know, Helen, do you know?”

“I don't know either, Miss Smith,” said Helen. “But it happened to my father.” The ____ children in the class laughed when they heard this.

Then boy said, “I ____ , Miss Smith! A man's hair becomes grey ____ because it's sixteen years ____ than his beard.”