机密

tā zhèng zài wán chéng yī xiàng jī mì de rèn wù

他正在完成一项机密的任务。

He is now doing a secret mission.

wǒ shōu dào yī fēng jī mì de xìn jiàn

我收到一封机密的信件。

I received a confidential letter.

jī mì de wén jiàn yào bǎo guǎn hǎo

机密的文件要保管好。

Confidential document should be well kept.

měi gè rén dōu yīng gāi yán shǒu guó jiā jī mì

每个人都应该严守国家机密。

Everyone should strictly guard his or her state secrets.

zhè shì yī xiàng jūn shì jī mì

这是一项军事机密。

This is a military secret.

fán shì yǔ zhè xiàng gōng chéng yǒu guān de rén yuán dōu bì xū yán shǒu jī mì

凡是与这项工程有关的人员都必须严守机密。

Everyone connected with the project was sworn to secrecy.