my (或 his 等) lips are sealed

used to convey that one will not discuss or reveal something

无可奉告

put (或 set) the seal on

give the final authorization to

最终授权；最终认可

the UN envoy hopes to set the seal on a lasting peace.

联合国特使希望持久和平能确定下来。

seal someone's (或 something's) fate

irrevocably determine or cause a bad or unpleasant outcome for someone (or something)

注定命运（常指产生不幸或不愉快的结局）

set (或 put) one's seal to (或 on)

mark with one's distinctive character

给…盖印；打上显明的烙印

it was the Stewart dynasty which most markedly set its seal on the place.

正是斯图亚特王朝在这个地方标上了它显明的印记。

seal off

To close tightly or surround with a barricade or cordon

封锁：用路障或封锁线使关得严实或包围

An unused wing of the hospital was sealed off.

一个未启用的医院侧厅被封锁了