声速差异伪像
参考答案：
组织中声速的差异会引起声束偏离直线传播，导致显示的图像与实际组织的位置不对应或形成失真图像。
I am not sure exactly how much money you will receive, but it will______cover your major expense.
A．firmly
B．roughly
C．constantly
D．frequently
