电气设备外壳同接地母线或局部接地极的连接，若使用铜线时应用面积不小于（）mm2。
参考答案：25
My uncle asked me ________ I ________ better or not.
A. whether , feel B. if , feeling C. whether ,felt
It is not easy to learn English well, but if you ____．You will succeed in the end.
A．hang about
B．hang on
C．hang onto
D．hang up
