下列关于声现象的说法中确的是() A . 小强的喊声大,说明他的音调高 B . 人耳听不到次声波,是因为响度太小 C . 接听电话时能根据音色来分辨不同的人 D . “长啸一声,山鸣谷应”——声音遇到障碍物反射,可以形成回声 答案:C,D . Why _____ so many money recently? I am bored to see you. A. are you borrowing B. have you been borrowing C. have you borrowed D. did you borrow