胃脘痛的多发年龄为
A.少年
B.青年
C.中青年
D.中老年
E.老年
参考答案:C
—Must we wear our school uniform this afternoon?
—No, you _____. All of us will go on an outing.[ ]
A. mustn't
B. can't
C. needn't
D. couldn't
NK细胞表面的主要标志性分子是( )
A.CD56
B.TCR
C.CIM
D.CD11a/CD18
E.CD16