第20题: [单项选择]患者,女,20岁。患地方性甲状腺肿,颈部肿大明显,其发病机制是()。 A. 缺铁 B. 缺碘 C. 缺钙 D. 维生素B缺乏 E. 内因子缺乏 参考答案:B 答案解析:地方性甲状腺肿又称为单纯性甲状腺肿,甲状腺素原料(碘)缺乏是发病主要原因,多见于内陆山区和半山区,由于土壤中的碘盐被冲洗流失,以致饮用水和食物中含碘量不足,甲状腺激素合成不足,分泌减少,反馈性刺激腺垂
第21题: [单项选择]{{B}}Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. The two speakers are classmates. B. Tire man is majoring in elementary education. C. The woman is majoring in elementary, education. D. The two speakers got to know each other in a class. 参考答案:C 答案解析:[听力原文]
W: Hi, Peter. I was surprised to see you in the class in children’s literature yesterday. Ar