Put a few drops of food colouring in the cistern and wait for 15 minutes. If the colouring appears in the toilet bowl, you have a leak.是什么意思_Put a few drops of food colouring in the cistern and wait for 15 minutes. If the colouring appears in the toilet bowl, you have a leak.在線翻譯_英語_讀音_用法_例句