indicator solution

例句：

1. 1. The pH indicator solution is used to test the acidity of the solution.
   pH指示剂溶液用于测试溶液的酸碱度。
2. 2.The chemical analysis requires the use of an indicator solution to detect the presence of certain chemicals.
   化学分析需要使用指示剂溶液来检测某些化学物质的存在。
3. 3.The doctor used the indicator solution to identify the patient's blood type.
   医生使用指示剂溶液来识别病人的血型。