用对称分量法分析中性点接地系统中某点C相断线故障的边界条件是什么？
参考答案：
△UkA=△UkB=0，IkA=0。（电压、电流为向量）
兖矿集团[2007]174号文件规定，编制采区及工作面设计或制定防冲安全技术措施时，综采（）工作面电站尾车距离工作面煤壁不小于（）米。
Which of the following would the nurse teach the mother of a child with leukemia who has an absolute neutrophil count of 900/mm3
A．The child should wear gloves when in contact with others.
B．The child should stay away from crowds of people.
C．The child should eat raw fruits and vegetables.
D．Anyone in direct contact with the child must wear a gown and mask.
