3 sentences

1. 他在给气球充气。

   tā zài gěi qì​qiú chōng​qì.

   He is inflating the balloon.

   Source: Dong Chinese Dictionary

2. 这个篮球的弹力已经减弱了，需要充气。

   zhè​ge lán​qiú de tán​lì yǐ​jīng jiǎn​ruò le, xū​yào chōng​qì.

   The basketball has lost its bounce and needs more air.

   Source: Dong Chinese Dictionary

3. 安全气囊在车辆发生碰撞时会迅速充气弹出。

   ān​quán​qì​náng zài chē​liàng fā​shēng pèng​zhuàng shí huì xùn​sù chōng​qì tán​chū.

   Airbags inflate and deploy quickly during a vehicle collision.

   Source: Dong Chinese Dictionary