具有电容滤波器的单相半波整流电路,若变压器副边有效值U=20V,当负载开路时,输出平均电压U0约为()。
A.9V
B.28.2V
C.8V
D.20V
参考答案:B
Professor Smith, together with his assistants, ________on the project day and night to meet the deadline. [ ]
A. work
B. working
C. is working
D. are working
静注肌松药产生肌松的顺序,正确的是()
A.眼肌颈部肌上肢肌下肢肌腹肌
B.腹肌下肢肌上肢肌颈部肌
C.眼肌上肢肌腹肌下肢肌颈部肌
D.眼部颈部肌腹肌上肢肌下肢肌
E.上述都不对