A:缺铁性贫血、地方性甲状腺肿
B:夜盲症、坏血病
C:脚气病、佝偻病
D:呆小症、肢端肥大症
(Ⅰ)a和c的值;
(Ⅱ)cos(B﹣C)的值.
—Sorry,I didn't.But now I know parking .