互感器的主要用途有()。
A.将大电量按一定比例变换为普通仪表可测量的小电量
B.向继电保护装置的测量系统供电
C.实现高电压系统的隔离
D.以上都正确
参考答案:D
A new bridge _______ across the river in Changsha and it is expected to open next year.
A. is built B is being built C. are built D. has been built
退行性核左移可见于()
A.急性中毒
B.急性失血
C.急性溶血
D.急性化脓性感染
E.败血症