在无限长螺线管中,磁场强度是均匀的
参考答案:对
——Why are you late for the meeting?
—— I got caught in the heavy rain, or I _______ earlier.
A.arrived
B.had arrived
C.would arrive
D.would have arrived
【3】 是一种信息隐蔽技术,目的在于将对象的使用者和对象的设计者分开。