a gym teacher的用法和样例：
- He went to college to be a gym teacher, with hopes of also training for the Olympics.
- "Suck in those stomachs, " the gym teacher said.
- I lift weights for an hour at a gym.
- "Suck in the stomaches,"the gym teacher said.
- "Smells like a gym down there," he told a friend.
- Took an hour of vigorous daily exercise at a gym.