Remove plug-in couplings from pressure and return lines .

从压力管和回流管上拆下插入式管接头。

Valid uses of bad couplings also occur for performance reasons .

因为性能原因，有时也会需要使用坏的耦合。

He pointed out that couplings between different species were sterile .

他指出，不同物种之间的联合是没有好处的。

New plug-in couplings are already screwed together .

新的插入式管接头已经拧在一起。

Insert canister and connect the two plug-in couplings .

插入碳罐并连接两个插入式管接头。