若函数f（x）=x2-ax-a在区间[0，2]上的最大值为1，则实数a等于 [ ]
A.-1
B.1
C.2
D.-2
答案：B
道岔尖轨顶面宽50mm及以上的断面处，尖轨顶面较基本轨顶面低于1mm及以上时，应及时修理或更换。
84. They’d like to see her daughter ____________, get married and have kids.
A．settle on
B．settle up
C．settle for
D．settle down
