题目

It took ______ building supplies to construct these energy-saving houses. It took brains, too. A. other thanB. more thanC. rather thanD. less than 答案：B“背日喷乎水，成虹霓之状”描写的是“人工虹”、该现象产生的原因是光的（ ）A．色散 B．直线传播 C．漫反射 D．镜面反射