门卫遇见不按照规定强行进入单位的人，虽然对方确实事出有因又没有隐患，但是不能变通执行门卫制度，让对方进入单位。（）
参考答案：错
The famous singer ______ where he was born and in 1930 he came to Beijing.
A．brought up
B．picked out
C．set up
D．grew up
已知一元二次方程x2-3x+2=0两根为x1、x2，则x1+x2=______．
