转矩极性鉴别器常常采用运算放大器经正反馈组成的( )电路检测速度调节器的输出电压Un。
A.多沿振荡
B.差动放大
C.施密特
D.双稳态
参考答案:C
单句改错。
1. People love to get together to eat and have a fun with each other. __________
2. He was not going to hold his breathe for her to apologize. __________
3. He could not have Yong Hui getting away to telling people lies. __________
4. It would be better if you were a bit thin. __________
5. They see a penniless young man wandered on the pavement. __________
6. I saw a man dressed in rag the other day. __________
7. They gave performances in pubs, for that they were paid in cash. __________
8. Imagine our excitement when we heard it on the radio the first time. __________
9. The carpet raised and at once they were in a thick rainforest. __________
10. The coffee is excellent quality and has been sold very well. __________
依据《注册安全工程师管理规定》,注册有效期满需要延续注册的,申请人应当在有效期满( )日前,按照《注册安全工程师管理规定》的程序提出申请。
A.15
B.30
C.60
D.90