截止频率越高，则系统的（）。
A.稳定性越好
B.快速性越好
C.稳态精度越高
D.抗干扰能力越强
参考答案：B
—Kate, do you know ___it is from here to the post office?
—About twenty minutes’ walk.
A．how long
B．how often
C．how far
D．how soon
