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

A. lacking of                      

B. lacking      

C. being lackcd                    

D. lack

淋巴细胞交叉配型的主要目的是（）

A.检测供者血清中有无抗受者淋巴细胞抗体

B.检测供者HLA抗原

C.检测受者血清中有无抗供者淋巴细胞抗体

D.检测受者HLA抗原

E.检测供者和受者的血型是否吻合