∵y=12（x-1）（x+5）=12x2+2x-52，
∴由对称轴公式，得对称轴是x=-b2a=-2．
—Could you tell me how your father usually goes to work?
—Yes. If it is fine, he ________ to his office.
A．will walk
B．will go on foot
C．walks
D．would go on foot
为什么发电机在检修中要做电气试验？
