我把信封重新封好，确保没人打开过。

I carefully ___resealed the envelope to make sure no one had opened it.

这份合同修改后需要重新公证。

This contract needs ___resealing by a notary after amendments.

为了防止漏水，我们需要重新密封浴缸的接缝。

We need to ___reseal the bathtub joints to prevent leaks.