linear flame propagation

例句：

1. 1.The fire spread linearly across the room.
   火沿着房间蔓延。
2. 2. The scientists studied the propagation of linear flames.
   科学家们研究了线性火焰的传播。
3. 3. The firefighters were able to control the linear flame propagation.
   消防员们能够控制线性火焰的传播。