碘缺乏可引起哪些症状
A. 甲状腺肿大
B. 流产
C. 克汀病
D. 高碘性甲状腺肿
E. 胎儿畸形
机体氟过量可能引起下列哪些症状
A. 氟斑牙
B. 大骨节病
C. 智力发育障碍
D. 氟骨症
E. 骨质疏松
It is improper to ____ (different) between pupils according to their family background.
He had been a strict father but was ____ (indulge) to his grandchildren.