___ darker now, we had to stay in the village for the fight.

A．It was getting

B．It getting

C．Getting

D．Being

设函数f(x)=-x(x-a)²(x∈R)，其中a∈R．
(1)当a=1时，求曲线y=f(x)在点(2，f(2))处的切线方程；
(2)当a≠0时，求函数f(x)的极大值和极小值，