5秒鍾不痛快馬桶試驗重大發現，3種洞眼解釋

Did you know that there are 3 different kinds of openings in your toilet?  For a long time, I was trying to figure out the mystery of slow flush in my toilet, and finally I found the explanation and solution. I have discovered this easy 5-second test, which will save your time and money by diagnosing the problem.