She likes _____ chess after class.[ ]
A. to play the
B. playing a
C. plays
D. playing
答案:D
Anfinsen以RNase为材料进行的变性一复性实验得出的结论是______。
流感病毒发生变异的形式有()
A.抗原转移、抗原漂移
B.抗原转移、抗原转换
C.抗原替换、抗原转换
D.抗原替换、抗原转移
E.抗原转换、抗原漂移