题目

The Ig Nobel Prizes praise research that makes you laugh and then think. The winners are allowed to make a one-minute speech with time kept by an eight-year-old! Every year, in Harvard' s Sanders Theatre, people watch the winners step forward to accept their prizes. These are physically handed out by real Nobel laureates （获得者）.Let' s have a look at some of them.The Empty Bladder （膀胱）ExperimentFour researchers at Georgia Institute of Technology found that animals above 3 kg empty their bladders in about 21 seconds. What is the purpose of this study? The researchers hope this w钓鱼时不能大声喧哗，因为鱼听到人说话声就会被吓走，这说明（    ）  A．声音从空气传入水中，音调发生了变化；B．只有空气能传播声音；C．声音在水中的速度比在空气中的速度小；D．空气和水都能传播声音。