Jenny nearly missed the flight ________ doing too much shopping.[ ]

A. as a result of  

B. on top of

C. in front of  

D. in need of

艾滋病被称为“20世纪的癟疫”，艾滋病毒以人体内的（）作为攻击目标。

A.红细胞

B.血红蛋白

C.淋巴细胞

D.神经系统