3 sentences

1. 面对对方的无理指责，他予以有力还击。

   miàn​duì duì​fāng de wú​lǐ zhǐ​zé, tā yǔ​yǐ yǒu​lì huán​jī.

   He delivered a forceful rebuttal to the other party's unreasonable accusations.

   Source: Dong Chinese Dictionary

2. 他在遭到歹徒袭击时奋力还击，被法院认定为正当防卫。

   tā zài zāo​dào dǎi​tú xí​jī shí fèn​lì huán​jī, bèi fǎ​yuàn rèn​dìng wéi zhèng​dàng fáng​wèi.

   He fought back when attacked by a thug, and the court ruled it as self-defense.

   Source: Dong Chinese Dictionary

3. 遭敌伏击后，我军迅速开火还击。

   zāo dí fú​jī hòu, wǒ jūn xùn​sù kāi​huǒ huán​jī.

   After being ambushed by the enemy, our army quickly returned fire.

   Source: Dong Chinese Dictionary