mechanical analysis of sand

例句：

1. 1. The machine is designed to be easy to operate.
   这台机器设计得易于操作。
2. 2. Mechanical engineering is a field of study that focuses on the design and construction of machines.
   机械工程是一门专注于设计和建造机器的学科。
3. 3. The new car has a mechanical gearbox that makes it more efficient.
   这款新车配备了机械变速箱，使其更加高效。