晶体管电压调压器必须与（）配套使用。
参考答案：硅整流发电机
— Must they clean and tidy the classroom now?
— No, they . It after school in the afternoon.
A．mustn’t; must clean
B．needn’t; must clean
C．mustn’t; need be cleaned
D．don’t have to; can be cleaned
我国人民民主专政社会主义国家的领导阶级是工农阶级。[ ]
