请把瓶塞塞紧，防止汽水跑气。

Please push the ___stopper tightly to prevent the soda from going flat.

这种新药被证明是炎症的有效抑制剂。

The new drug proved to be an effective ___stopper for inflammation.

会议中的突发事件成为了讨论的终止符。

The unexpected incident in the meeting became the ___stoppage to the discussion.