一台信号发生器的输出阻抗为600Ω，当带上600的负载后，负载上得到的信号幅度相当于开路输出幅度的（）。
A、不变
B、1/2
C、1/4
参考答案：B
Jane sings very well, and ______.[ ]
A. so did her sister
B. so does her sister
C. her sister does so
D. so does her sisters
膨胀物质是有边界的。
