如图,椭圆E: x 2 a 2 + y 2 b 2 =1(a>b>0) 的右焦点F 2 与抛物线y 2 =4x的焦点重合,过F 2 作与x轴垂直的直线l与椭圆交于S、T两点,与抛物线交于C、D两点,且 |CD| |ST| =2 2 . (Ⅰ)求椭圆E的方程; (Ⅱ)若过点M(2,0)的直线与椭圆E相交于两点A,B,设P为椭圆E上一点,且满足 OA + OB =t OP (O为坐标原点),当 | PA - PB |< 2 5 3 时,求实数t的取值范围.
【单选题】They said I shouldn t have done that to help him. But I don't regret _____what I thought was right. A). to do B). to have done C). having done D). being done
【判断题】Legend ( 传说) has it that Santa Claus will enter each house through the chimney and bring gifts to well-behaved children on Christmas Eve. .翻译为“据传说,圣诞老人会在圣诞夜从烟囱进入每户人家,给熟睡的孩子带来礼物。”