已知动圆:x2+y2-2axcos θ-2bysin θ=0(a,b是正常数,a≠b,θ是参数),则圆心的轨迹是________
椭圆
Almost all job applicants are determined to leave a good () on a potential employer.
A.illusion
B.impression
C.reflection
D.reputation
根据《中国移动900/1800MHzTDMA数字蜂窝移动通信无线网工程验收规范》,同轴电缆的最小弯曲半径为其外径的()倍。
A.3
B.6
C.10
D.15