注：第一和第二止回阀模块的阀座和弹簧是不可互换的。较重的弹簧和较小直径的阀座属于第一止回阀模块。

Note: the seats and springs of the first and second check modules are not interchangeable. The heavier spring and smaller diameter seat belong with the first check module.

youdao

尽管NIEM通过提供公共定义和技术而有助于互操作，但是两个使用不同niem子集的IEPD的XML文档是不可互换的。

Although NIEM helps interoperability by providing common definitions and techniques, XML documents from two IEPDs that use different subsets of NIEM are not interchangeable.

youdao

如果没有1969年的那次互换，像现在白宫和克里姆林宫正在讨论的那种，我的父母永远不可能结合。

Without a 1969 exchange like the one now being discussed between the White House and the Kremlin, my parents would never have married.

youdao