当缺乏此维生素时，幼龄动物会出现骨骼变软，成年动物出现骨质疏松的疾病，此疾病为（）

A.维生素B₁缺乏症

B.维生素B₂缺乏症

C.维生素B₆缺乏症

D.维生素D缺乏症

E.胆碱缺乏症

It is useless to argue with him. You might just____  go to the seaside to argue with the sea.

A．as well

B．well

C．as well as

D．so well as