在自动平衡式浮子液位计中,由于采用了()作为将液位高度转换为电信号的转换元件,因而测量精度大为提高。
A.电子放大器
B.位移放大器
C.差动变压器
D.可逆电动机
参考答案:C
It was not until the entrance exams were in sight that that I had so many books to cover and so many exercises to finish.
A.I realized
B.did I realize
C.had I realized
D.I had realized
锅炉冷态上水时间夏季为()小时,冬季为()小时。