现有船舶初次检验的船舶图纸和资料应按该船()时适用的国内海船海船法规和相应的规范进行审查,下列不正确的为:()
A、安放龙骨
B、下水前
C、转户
D、完工
参考答案:B, C, D
—How long have Mr. and Mrs. _____?
—For more than twenty years. [ ]
A. married
B. been marry
C. get married
D. been married
单相半波整流电路如图示,已知输入电压有效值Ui负载上得到的电压Uo为()。
A.0.45Ui
B. 0.9Ui
C. Ui
D. 1.2Ui