如题图所示二端口网络，其Z参数中的z₁₁=______，z₁₂=______。

A. Teach their young how to swim.
B. Mate and lay eggs.
C. Hide from predators.
D. Eat different kinds of fish.

A. Change a partner.
B. Ask the teacher for advice.
C. Meet his partner in the mid-town.
D. Make a compromise with his partner.

A. He"s improved the way he looks
B. He manages his time well
C. He looks happier lately
D. He follows directions more carefully now

A. 知识的传授
B. 培养学生的心理素质
C. 发展学生的能力
D. 培养学生的良好的思想品德