Because of           construction materials, the project had to be put off.       [ ]

A. lacking of                      

B. lacking      

C. being lackcd                    

D. lack

关于痴呆的治疗用药正确的是（）

A.抗氧化、抗自由基

B.保护和营养神经

C.神经生长因子

D.褪黑素