磁电系仪表的功率消耗有何特点?
参考答案:
因为磁电系仪表永久磁铁的磁场很强,动圈通过很小的电流就能产生很大的力矩,因此仪表本身所消耗的功率很低。
I don't know when Martin _____ I'll meet him at the airport when he _____. [ ]
A. will return; return
B. returns; will return
C. returned; returned
D. will return; returns
脑复苏时采用降温疗法时,体温一般降至()。
A.30~33℃
B.22~26℃
C.26~30℃
D.18~22℃
E.33~35℃