单项选择题 are 的过去式是were（）

单项选择题 In the movie Mr. Holland’s Opus, rock n’ roll so much was regarded as “a message sent from the evil” by many American parents in the 1960s. Why did they fear rock n’ roll so much? Which one of the following is not the reason? A、They believed rock n’ roll could lead to a breakdown of discipline.B、They believed rock n’ roll could mislead their children to drug use and sexual liberation.C、They believed rock n’ roll is closely related to Hippie culture. To love rock n’ roll meant to lead a Hippie lifestyle.D、Because it’s hard for parents to embrace new things, especially rock n’ roll, the new genre of radical pop music.

单项选择题 通信设备室机柜发生火灾后，可以使用（）灭火