5 sentences

1. 防空警报突然响了起来。

   fáng​kōng jǐng​bào tū​rán xiǎng le qi​lai.

   The air raid siren suddenly went off.

   Source: Dong Chinese Dictionary

2. 防空部队击落了一架敌机。

   fáng​kōng bù​duì jī​luò le yī jià dí​jī.

   The anti-aircraft units shot down an enemy plane.

   Source: Dong Chinese Dictionary

3. 政府组织了全市防空演习。

   zhèng​fǔ zǔ​zhī le quán shì fáng​kōng yǎn​xí.

   The government organized a city-wide air defense drill.

   Source: Dong Chinese Dictionary

4. 听到防空警报，大家都迅速躲进了防空洞。

   tīng​dào fáng​kōng jǐng​bào, dà​jiā dōu xùn​sù duǒ jìn le fáng​kōng​dòng.

   Upon hearing the air raid siren, everyone quickly took cover in the air raid shelter.

   Source: Dong Chinese Dictionary

5. 防空部队成功地打下了一架敌方的侦察机。

   fáng​kōng bù​duì chéng​gōng de dǎ​xià le yī jià dí​fāng de zhēn​chá​jī.

   The anti-aircraft units successfully shot down an enemy reconnaissance plane.

   Source: Dong Chinese Dictionary