接种麻疹疫苗后产生对麻疹的抵抗能力，这反映了（）
A.抗原的特异性
B.抗原的交叉反应性
C.病毒的超感染
D.先天免疫
参考答案：A
婴儿想吃奶的反应有：小嘴来回觅食，小嘴有吸吮动作，哭闹等表现。
Under the regulations for cargo vessels，which statement is TRUE concerning fireman’s outfits?（）
A.If a vessel carries two outfits，they may be stored in the same location
B.Each fireman's outfit shall contain a flame safety lamp of an approved type
C.Each fireman's outfit shall contain a fresh-air breathing apparatus
D.All of the above
