mechanical sources

例句：

1. 1.The machine is designed to be easy to use.
   这台机器设计得易于使用。
2. 2.The car has a mechanical gearbox.
   这辆车有一个机械变速箱。
3. 3. The robot was mechanized by a team of engineers.
   一个工程团队为机器人进行了机械化改造。