a polite child的用法和样例：
- "A polite child grows up to get the friends and the dates and the job interviews," she says, "because people respond to good manners.
- He moved aside for her with a polite bow.
- "How do you do?" is a polite formula.
- "Shut up" is not a polite expression.
- We were ushered in by a polite waiter.
- She tried to wrap up a censure in a polite formula.