We couldn't go out _____ it is too cold today. [ ]
A. but
B. if
C. or
D. because
答案:D
并发操作可能会产生哪几类数据不一致?用什么方法能避免各种不一致的情况?
计算题:当室温为30℃,电机运行实测温度75℃,电机绝缘等级为A级绝缘,求:电机温升是多少?电机工作是否正常?