upper flat plate

例句：

1. 1.The upper flat plate is the main part of the machine where all the moving parts are mounted.
   上平板是机器的主要部分，所有移动部件都安装在此处。
2. 2.The upper flat plate is used to support the lower flat plate during the manufacturing process.
   上平板在制造过程中用于支撑下平板。
3. 3.The upper flat plate is crucial for ensuring the smooth operation of the machine.
   上平板对于确保机器平稳运行至关重要。