(判断题)18: 按照驱动电路加在器件控制端和主电路之间信号的性质,电力电子器件分为电压控制器件和电流控制器件。 A: 错误 B: 正确 ...

(多选题)12: 电力电子系统由：（）、（）和以电力电子器件为主的（）组成。 A: 控制电路 B: 驱动电路 C: 主电路 D: 运算电路 ...

(单选题)6: 三相桥式全控整流电路中晶闸管承受的电压波形与三相半波时（），晶闸管承受最大正、反向电压的关系（）。 A: 相同，相同 B: 不同，相同 C: 相同，不同 D: 不同，不同 ...

(单选题)1: We had warned him __ the danger but he turned a deaf ear to our warning. A: at B: of C: / D: with ...

(单选题)8: This coastal area ________ a national wildlife reserve last year. A: was named B: named C: is named D: Names ...

(单选题)21: I ____________to the cinema a lot, but I never get the time now. A: am used to going B: used to go C: am used to go D: used to going ...

(单选题)22: The teacher says that Xiao Yu ______ work harder. A: will have to B: has rather C: would rather to D: has better ...

(单选题)16: The middle aged man was seen ____out of the house on the afternoon of the murder. A: came B: come C: to come D: have come ...

(单选题)4: They took ________ measures to prevent poisonous gases from escaping in the chemical plant. A: fruitful B: beneficial C: effective D: influential ...

(单选题)24: I ________ thank you too much for all your help to my son while we were away from home. A: won’t B: can’t C: can D: will ...