recess in rotor

例句：

1. 1. The engineer designed the machine to have a recess in the rotor for better efficiency.
   工程师设计的机器在转子中有一个空腔，以提高效率。
2. 2. The rotor was removed from the machine to inspect the recess.
   为了检查转子中的空腔，将转子从机器上拆了下来。
3. 3. The recess in the rotor is crucial for the machine's operation.
   转子中的空腔对机器的运行至关重要。