1. Electric power is the antecedence to the development of the national economic. ���Ҿ��õķ�չ�����������С�
2. It should accord to the regulate of law, the requirement of occupation or duty, the legal action, the action of antecedence and so on. ����Ϊ�����е�������Դ�ڷ������Ĺ涨�ġ�ְҵ��ְ�������Ҫ������ġ����ڷ�����Ϊ�����ġ�������Ϊ����ĵȷ�������
3. It has an important effect on the antecedence tunnel and results in displacement and stress increase when the later tunnel is excavated. �����������ڶ���������Χ�ҵ����������кܴ�Ӱ�죬�����������ڵ���������������λ�ƺ�Ӧ�����������