一元二次方程x2-2x+1=0的根为______．
∵x2-2x+1=0
∴（x-1）2=0
∴x1=x2=1．
—Could you please tell _______________________?
—Sure. Though I am a little nervous, I would love to.
A．when we shall have the graduation ceremony
B．what are you going to say at the graduation ceremony
C．where will you hold the graduation ceremony
D．if you are going to give a speech at the graduation ceremony
机械加工中夹具的合理使用可保证加工精度，提高劳动生产率。( )
