自控系统在工艺生产负荷正常、仪表运行平稳情况下,自控系统出现故障的原因主要来自于()。
A.调节器自身故障
B.测量系统故障
C.执行器系统故障
D.以上三项
参考答案:D
There are plenty of _______ in our school. They work very hard.
A.woman teachers
B.woman teacher
C.women teachers
D.women teacher
从()开始,普遍采用砖石筑墓室,木椁墓室逐渐被取代。
A、秦
B、汉
C、魏