Why do some people tie thin piece of cloth on mouth of wate taps?

What are the example of speech courtesy? How can you congratulate a coworker for a new baby? What do you do if someone tells you to f off? What does cheking you out mean? What is a more formal way of saying That is a terrible way to go about things? What do you called a person that follows the same routine as you do? How do people in Britain say goodbye? What is La prochaine fois que t'arrive c'est bon? How do you address an envelope to a wife only if her husband is a doctor - do you refer to her as Mrs. or Dr.? What is appropriate behaviour? How do you say behave in Chinese? How do you write a goodbye letter to a nice person that you don't know that well? What does the idiom do something behind ones back mean? What are the procedures to conducting a flag casing ceremony? How do you say keep your hands to yourself in French? What is the proper gothic attire? What does respectfully yours mean at the end of a letter? What is the different between Ms and Mrs? What is important to remember in regards to dress code? How do you say 'i am not selfish' in french?