放大电路的放大倍数是输出变化量的幅值与输入变化量的幅值之比。()
参考答案：对
解释下列词语。
①戏谑：____________________________________。
②大言不惭：____________________________________。
③步履蹒跚：____________________________________。
---What made you so_________?
---Oh, Mr Wu told us a funny story and it made us _________.
A．happy, to laugh
B．happily, to laugh
C．happy, laugh
D．happily, laugh
