当L＞d时（图）垂直接地极的接地电阻可利用下列等式中（）计算。
A.A
B.B
C.C
D.D
参考答案：A
My grandmother likes to watch me________. [ ]
A. read and write
B. reads and writes
C. to read and write
D. reading and write
水的衰减系数是
A．0
B．1
C．2
D．10
E．100
