a helping verb的用法和样例：
- Now that you’ve seen this list, do you understand what a helping verb is?
- He never stands aside when he is needed to lend a helping hand.
- She is quite a help to her mother.
- The servants were more of a hindrance than a help (to me).
- Instead of exulting over his failure, you should have lent him a helping hand.
- Now the boy is quite a help to his mother.