按要求变换句型

1. I'm free tomorrow. (改为同义句)

    I __________ __________ tomorrow.

2. My pen pal comes from Canada. (改为一般疑问句)

    __________ your pen pal __________ from Canada?

3. We have some vegetables here. (改为否定句)

    We __________ have __________ vegetables here.

4. I work in an office. (对划线部分提问)

    __________ __________ you work?

5. I have three books. (对划线部分提问)

    __________ __________ books do you have?

香农定理从定量的角度描述了“带宽”与“速率”的关系。在香农定理的公式中，与信道的最大传输速率相关的参数主要有信道带宽与________。

A．频率特性

B．信噪比

C．相位特性

D．噪声功率