题目

   When building houses, people used to think about not only the climate of the areas but also the building materials and the fashions for their houses. However, since electricity became more and more expensive, people began to pay much more attention to the energy they could get for their houses and the new ways they could find to protect their houses from both cold and heat.     Houses of an old yet new type have been widely built. In some parts of the world, people share their houses with their livestock (家畜). During cold weather, they gather their cows, goats, or other ani下列关于声音的表述，你认为正确的是 ( )A. 超声波的频率小于人耳能听到的声音频率B. 街道两旁种花植树，可以减弱噪声的产生C. 公共场所要小声交谈，减小声音的响度D. 做“B超”检查，利用了声波传递能量的特性