一台4对磁极的异步电动机，接在工频电源上，其转差率为2%，试求异步电动机的转速？
参考答案：
答：此时异步电动机的转速为735r／min。
真理向谬误转化的原因，主要在于该真理[ ]
①超出了其适用的条件和范围
②只为少数人所坚持
③背离了主观与客观、认识与实践的具体的历史的统一
④在实践中一时未能达到预期的结果
A、①③
B、②③
C、①④
D、②④
When I met him the other day，it was the first time we________each other since we were at school.[ ]
A．saw
B．had seen
C．were seeing
D．have seen
