Antigenic shift refers to thecombination of two different strains of influenza; in contrast,antigenic drift refers to the natural mutation of a single strain of influenza.
A. influenza; in contrast, antigenicdrift refers to the natural mutation of a single strain of influenza
B. influenza, different than thenatural mutation of a single strain, known as antigenic drift
C. influenza, in contrast to thenatural mutation of a single strain, known as antigenic drift
D. influenza, different than antigenic drift, which refers to thenatural mutation of a single strain of influenza
E. influenza; in contrast to antigenic drift, which refers to thenatural mutation of a single strain of influenza作者: gdboy8888 时间: 2012-3-4 19:28
选A。。B和D的different than 要改为different from..C我觉得in contrast