To test water, you simply insert a sample and, within seconds, it either displays a red light, indicating contaminated water, or a green light, indicating the sample is safe.
要检测水质，你只需要把水样放进去 等待几秒钟 如果红灯亮，代表水样受到污染 如果绿灯亮，代表这里的水是安全的