安装带有短路保护的漏电保护器，必须保证在电弧喷出方向有足够的飞弧距离。第五章P83
参考答案：对
They came here several years ago, and ____ ever since. [ ]
A. settled
B. settled down
C. lived in
D. have settled down
假如希望20年后账户中有500000元，年复利10%，期初应存入（）元。
A.65440.52
B.83602.54
C.74321.81
D.63532.45
