Since the end of the war, many of the priceless antiques ______ to their rightful owners．

A．have returned

B．had returned

C．had been returned

D．have been returned

子宫脱垂最常见的原因为

A．长期腹压增加

B．分娩损伤

C．盆底发育不良

D．盆底退行性变

E．产褥期过度劳累