— Why does the lake smell terrible? 

— Because large quantities of water _________.[ ]

A. have been polluted      

B. has polluted    

C. have polluted          

D. has been polluted

《痹论》痹病痛久的原因是（）。

A.入脏伤正

B.留于皮肤间

C.留连筋骨间

D.入腑伤气

E.以上均不是