________such heavy loss during the financial crisis, the businessman didn't have the courage to go on.
A:To suffer
B:Suffering
C:Having suffered
D:Suffered
材料一:英国割占香港地区示意图
点A、B、C是平面内不在同一条直线上的三点,点D是平面内任意一点,若A,B,C,D四点恰能构成一个平行四边形,则在平面内符合这样条件的点D有( )