不是朊粒主要特点的是（）
A.引起人和动物中枢神经退化性病变
B.不含有RNA
C.是蛋白酶抗性蛋白
D.仅含DNA
E.具有传染性
参考答案：D
句型转换。
1. My house is on Green Street. (就画线部分提问)
_____ is _____ house?
2. It's time for lunch. （改同义句）
It's time _____ _____ lunch.
3. Miss Gao is our English teacher. (改同义句)
Miss Gao _____ _____ English.
4. I had a busy weekend . (一般疑问句)
_____ you _____ a busy weekend?
5. He is doing his homework. now. (用 every day 代替now, 且改否定句)
He _____ _____ his homework every day.
下列有关旋转变流机的说法，正确的是：（）.
A.直流电动机是交流发电机的原动力
B.交流发电机是直流发电机的原动力
C.直流发电机是交流发电机的负载
D.交流发电机是直流电动机的负载
