x2+4x+2=0．
x2+4x+22=-2+22，
即（x+2）2=2
x+2=±2，
x1=-2+2，x2=-2-2．
I with Lily _______ at the cinema at eight yesterday evening. [ ]
A. am
B. was
C. are
D. were
下列生活场景中，通过做功来改变物体内能的是[ ]
A．搓动双手感到暖和
B．用嘴向手“哈气”感到暖和
C．冬天晒太阳感到暖和
D．围坐火炉烤火感到暖和
