4 sentences

1. 行军时，他因为体力不支而落伍了。

   xíng​jūn shí, tā yīn​wèi tǐ​lì bù​zhī ér luò​wǔ le.

   During the march, he fell behind because he lacked the physical strength to keep up.

   Source: Dong Chinese Dictionary

2. 他在终点线前因为体力不支倒下了。

   tā zài zhōng​diǎn​xiàn qián yīn​wèi tǐ​lì bù​zhī dǎo​xià le.

   He collapsed before reaching the finish line due to exhaustion.

   Source: Dong Chinese Dictionary

3. 由于体力不支，他渐渐无法跟进前面的运动员。

   yóu​yú tǐ​lì bù​zhī, tā jiàn​jiàn wú​fǎ gēn​jìn qián​miàn de yùn​dòng​yuán.

   Due to physical exhaustion, he gradually failed to keep up with the athletes ahead.

   Source: Dong Chinese Dictionary

4. 面对猛烈的攻击，敌军体力不支，最终溃败而北。

   miàn​duì měng​liè de gōng​jī, dí​jūn tǐ​lì bù​zhī, zuì​zhōng kuì​bài ér běi.

   Facing a fierce attack, the enemy forces were exhausted and eventually suffered a crushing defeat and fled.

   Source: Dong Chinese Dictionary