食品包装必须保持密封。

Shípǐn bāozhuāng bìxū bǎochí mìfēng.

Food packaging must be kept sealed.

文件袋要密封好，防止湿气进入。

Wénjiàn dài yào mìfēng hǎo, fángzhǐ shīqì jìnrù.

The document bag should be properly sealed to prevent moisture from entering.

这个容器可以密封保存食物。

Zhège róngqì kěyǐ mìfēng bǎocún shíwù.

This container can seal and preserve food.