下面的()不是差压变送器无指示的故障原因。
A.仪表未校准
B.信号线脱落或电源故障
C.安全栅坏了
D.电路板损坏
参考答案:A
Only when I made it to the train station _______ that I had left my ticket at home.
A.have I realized
B.did I realize
C.had I realized
D.would I realize
中间再热机组再热蒸汽压力取得越高,热经济性越好。