在带电的电流互感器二次回路上工作时，工作中禁止将回路的保护接地点断开。
参考答案：对
There are eight foreign teachers in our school, five of _____ are young ladies.[ ]
A. them
B. whom
C. who
D. which
π/4-QPSK的改进体现在哪些方面？
