钙沉积于前弹性层( )
A．老年B．角膜带状变性C．格子状角膜营养不良D．颗粒状角膜营养不良E．Fuch角膜内皮营养不良
参考答案：B
直线l：2x-3y+12=0与x轴、y轴分别交于A、B两点，则以A为焦点，经过B点的椭圆的标准方程是______．
An investor buys two calls and one put on ABC stock, all with a strike price of $45. The calls cost $5 each, and the put costs $4. If the investor closes the position when ABC is priced at $55, the investor's per share gain or loss is :
A．
B．
C．
