A:可以制造自由电荷
B:可以使闭合电路中有持续电流
C:可以使电路两端有一定的电压
D:可以将机械能转化为电能
读一读,写一写
①— Are there any ____ ?
— Yes, there are.
②There are many tall ____ in my city.
③There is a ____ above the river.
④- Are there any houses in the ____?
-Yes, there are.
据材料一、二,指出秦汉两朝在实行思想控制的具体方式上有何差异?