在一周内体育老师对某运动员进行了5次百米短跑测试，若想了解该运动员的成绩是否稳定，老师需要知道他5次成绩的[ ]

A.平均数

B.方差

C.中位数

D.众数

We don't need to do extra work this evening. The day's work was almost ______ now.[      ]

A. at the end  

B. at an end  

C. at one end    

D. at our end