方程x(x﹣2)=x的根是[ ]
A.x=0
B.x=2
C.x1=0,x2=2
D.x1=0,x2=3
答案:D
小医生,下列各句均有一处错误,请找出并改正。
1.At the head of the queue was two old women.__________
2.You don't need turn on the radio.__________
3.They are all places of interests in China.__________
4.I can draw a picture use my left hand.__________
5.Every day he made one of the animals jump into the river.__________
冲裁模的凸模、凹模工作部分的硬度应保证()。
A、HRC20~28;
B、HRC30~38;
C、HRC58~62。