已知点F1 (-5 ,0 ),F2(5 ,0) 且有|PF1|+|PF2|=10 ,则点P的轨迹是 [ ]
A.椭圆
B.双曲线
C.线段
D.两条射线
答案:C
合同法不以平等协商和等价有偿为原则。()
—_____ is your office away from here?
—Just ten minutes'walk. [ ]
A. How soon
B. How far
C. How often
D. How long