mechanical smoke control

例句：

1. 1. The machine is designed to perform a specific task.
   这台机器被设计来执行特定的任务。
2. 2. Mechanical engineers are responsible for designing and building machines.
   机械工程师负责设计和建造机器。
3. 3.The mechanical parts of the car need to be replaced regularly.
   汽车的机械部件需要定期更换。