Kate didn't go to the movie last Sunday because she had to ______ her sick mother at home.        [ ]

A. look at            

B. look up          

C. look after

关于原发性肝癌，哪项不正确

A．黄曲霉毒素可能与肝癌发病有关

B．胆汁性肝硬化与肝癌的发生无关

C．乙型肝炎病毒为肝癌的直接病因

D．肝内胆管细胞发生的癌肿