兴奋剂

例句：

1. 1. The athlete was given an illegal substance as a performance-enhancing drug.
   这位运动员被给予了一种作为性能增强药物的非法物质。
2. 2. The doctor prescribed the patient some stimulants to help him stay awake during surgery.
   医生给病人开了一些兴奋剂，以帮助他在手术期间保持清醒。
3. 3. Some athletes use stimulants to increase their endurance and speed during competitions.
   一些运动员使用兴奋剂来增加他们在比赛中的耐力和速度。