act as a poison的用法和样例：
- Alcoholic drinks act as a poison to a child.
- But as research continues, some experts worry that if people take too much vitamin D, it might act as a poison.
- The forest will act as a defense against desert dust.
- Maybe I can act as a messenger for you.
- A trained dog can act as a guide to a blind person.
- The substance has been scheduled as a poison.