Simon lived in Beijing _____ the years 2002-2004. [ ]
A. during
B. between
C. in
D. at
答案:A
人IgE分子不存在()
A.自身抗原
B.独特型抗原
C.同种型抗原
D.同种异型抗原
E.过敏原
小儿泄泻发病率较高的季节是()
A.春夏
B.夏秋
C.秋冬
D.冬春
E.四季无差异