受众
参考答案：从狭义上说，受众是大众传播的信息受传者；而从广义上来看，一切在信息交流活动中的信息接受方，都可以称为“受众”。
按要求改写下列句子。
1. He isn't confident in himself. (改为同义句)
He _____ _____ _____ in himself.
2. I'm not good at maths. (改为同义句)
I _____ _____ _____ maths.
3. Pwter will improve his spelling. (改为一般疑问句)
_____ Peter _____ his selling?
4. We have a piece of paper. (就划线部分提问)
_____ _____ _____of paper do you have?
5. She didn't go to school because she was ill. (改为同义句)
She didn't go to school _____ _____ her illness.
PET显像探测的射线（）
A.X射线
B.α射线
C.β射线
D.γ射线
E.中子
