抗体对病毒的中和作用主要是
A．抑制病毒生物合成B．诱导干扰素产生C．阻止病毒与靶细胞结合D．中和病毒毒素E．杀伤细胞内的病毒
参考答案：C
— Any news about Bill Clinton?
— He left power three years ago and has a little now and a little then been _____. [ ]
A. heard of since
B. heard since
C. heard before
D. heard of before
单纯组织固定液易燃易爆，一般应配成饱和溶液储藏的是（）
A.甲醛
B.重铬酸钾
C.锇酸
D.苦味酸
E.铬酸
