有些幼儿常服钙片,仍因缺钙患佝偻病,原因可能是缺乏( )
A:含铁的无机盐
B:蛋白质
C:维生素D
D:维生素C
请回答:
—The boy can speak both English and Japanese _________ he is only ten.
—Wow, what a clever boy!