To her amazement, when she returned home that afternoon, the digits of the Celsius and Fahrenheit temperatures were again in reverse of one another! What were the morning and afternoon temperature readings?- Leon J. Taub, Farming-dale State College, Farmingdale, NY. 原文传递 原文传递并翻译 ...
A toothbrush is used to clean teeth by removing plaque and debris from surfaces of the teeth as well to clean gum tissue surrounding teeth. Conventional toothbrushes typically have a head having tufts of bristles and may also have other types of cleaning structures. A variety of toothbrush ...