放大器放大的实质是输入信号控制下,把()输出。
A.输人电压转化为信号电压
B.输人电流转化为信号电流
C.电源功率转化为信号功率
D.输大功率转化为信号功率
参考答案:C
句型转换。
1. She does her homework every day. (改为否定句)
She her homework every day.
2. It's time for breakfast. (同义句转换)
It's time breakfast.
3. Sandy helps Kitty and Kitty helps Sandy. (同义句转换)
Sandy and Kitty help .
4. I go to school every day. (用Millie代替I作主语)
Millie ______ to school every day.
5. I want to go to China's Space Museum. (同义句转换)
I go to China's Space Museum.
实施健康教育计划要从哪方面控制
A.社区卫生服务资源
B.社区特定的家庭健康问题
C.社区特定的个人健康问题
D.社区特定的人群健康问题
E.时间控制、质量控制、对象控制