组胺 H2 受体拮抗剂西米替丁有以下哪些作用:()
A.抗组胺作用
B.抗胃酸分泌作用
C.增强免疫功能
D.抗雄激素作用
E.抗菌作用
参考答案:A,B,C,D
金黄色葡萄球菌感染见于
A.甲状腺功能减低症B.苯丙酮尿症C.胸腺发育不全D.21-三体综合征E.手足搐搦症
The young tennis player has often _____ famous players, but so far he has always been beaten.[ ]
A. competed for
B. competed over
C. competed with
D. competed in