in proper working order meaning in Chinese

• 工作正常

• proper:    adj. 1.适当的，相当的；正当的 ...
• working order:    (机器等)正常运转状态，良好状态。
• proper order:    正确次序

Examples

1. You must keep your brakes in proper working order
   须确保煞车掣操作正常。