办公室照明通常采用()作为电源连接线。
A.RV型
B.BV型
C.BX型
D.BLX型
E.BVV型
参考答案：B, C
Nowadays opportunities to find well-paid jobs were far from ______. [ ]
A. abundant
B. abundance
C. accurate
D. appropriate
有a、b、c三个数，已知a6=24，ac=36，bc=54，求a+b+c=( )
A．23 B．21 C．19 D．17
