---Can you sing _________ dance, Gina?
---I can sing, Miss Xu.
设F1、F2是椭圆E:x2a2+y2b2=1a>b>0的左、右焦点,P为直线x=3a2上一点,△F2PF1是底角为30°的等腰三角形,则E的离心率为( )
0°经线称为( )
He said that it was wrong flowers and leaves.
用配方法解方程x2+4x-1=0,下列配方结果正确的是( )