恶性葡萄胎与良性葡萄胎的主要不同点在于（）。

A.可见胎盘绒毛间质水肿、增大

B.滋养层细胞增生，可见核分裂象，细胞有异型性

C.绒毛消失

D.绒毛侵犯子宫壁深层肌

E.间质血管消失

The city is well known for its education of good quality, however, its standards of education have __         in recent years .  

A．distributed

B．contributed

C．cancelled

D．declined