He is mowing the lawn ____________ the fire alarm begins ringing.
举一反三
- No sooner _________ mowing the lawn than it started raining.
- Noticing the fire, Tom stops ____ up the fire station. A: to ring B: ringing C: rang
- 1.Everyone should know where the nearest fire alarm box is located and where exits, fire escapes, and fire doors are.
- A fire alarm should never be ignored. A: 正确 B: 错误
- 中国大学MOOC: A fire alarm should never be ignored.