题目内容
(请给出正确答案)
[主观题]
Ultrasonic frequencies are ______.A.inaudibleB.excessively fastC.characterized by a great
Ultrasonic frequencies are ______.
A.inaudible
B.excessively fast
C.characterized by a great amplitude
D.death rays
如搜索结果不匹配,请 联系老师 获取答案