请确保瓶子密封好以防液体泄漏。

Make sure the bottle is tightly ___sealed to prevent any leaks.

合同一签字盖章就正式生效了。

The contract became legally binding once it was ___sealed by both parties.

医生戴着密封的口罩以防病毒传播。

The doctor wore a ___sealed mask to prevent virus transmission.

这份证书上有官方的密封印记。

The certificate bears an official ___sealed stamp.