Complaining is as useful for people 's minds as a whistle vent is for a teakettle .
抱怨对人们头脑的作用如同一个烧茶壶的口哨阀门的作用一样。
To eliminate lime and mineral deposits in a teakettle , bring 3 cups full-strength white vinegar to a full boil for five minutes and leave the vinegar in the kettle overnight . Rinse out with cold water the next day .
