If we forgave criminals, we might become a society of endless excuses       no one accepts responsibility for anything．

A．which

B．where

C．when

D．as

极化会对晶体结构产生显著影响，可使键性由（）过渡，最终使晶体结构类型发生变化。

A.共价键向离子键

B.离子键向共价键

C.金属键向共价键

D.键金属向离子键