单项选择题 单相桥式整流电路变压器次级电压为10V(有效值),则每个整流二极管所承受的最大反向电压为( )。A. 10VB. , 14.14VC. 20VD. 28.28V

单项选择题 According to the passage， which of the following factors might spoil the tourist’s fun at Mediterranean resorts and beaches ？ A. Polluted water B. Crowded buses C. Traffic jams D. Rainy weather

判断题 In English, most passive sentences use the passive voice, whose syntactic structure is subject +be +the past participle of the verb. A、正确 B、错误