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
参考答案:E
There are no calories in water, so you can drink it ______ getting fat. [ ]
A. of
B. with
C. for
D. without
急性心包炎心包积液时最突出的症状是()
A.心前区疼痛
B.发热
C.呼吸困难
D.声音嘶哑
E.吞咽困难