fluorescent indicator

例句：

1. 1. The fluorescent indicator on the wall helps us find our way in the dark.
   墙上的荧光指示剂在黑暗中帮助我们找到方向。
2. 2. The doctor used a fluorescent indicator to detect the bacteria in the patient's blood.
   医生使用荧光指示剂来检测病人血液中的细菌。
3. 3. The fluorescent indicator was so bright that it could be seen from a distance.
   荧光指示剂非常亮，可以从远处看到。