【单选题】A psychrometer has two thermometers that provide dry bulb and wet bulb temperatures. By comparing these two temperature readings with a set of tables you can determine the ______.
【简答题】阅读理解。 About 130 years ago,Thomas Edison invented thelight bulb. His bulb turned night into day,but today manypeople want to turn off the light. The European Union( 欧盟) has decided that peo-ple should ...