促进钙磷吸收，缺乏可导致佝偻病的是（）
A.维生素B1
B.维生素B
C.维生素B12
D.维生素C
E.维生素D
参考答案：E
正常的声环境噪声范围是（）
We should all remember that some great scientific discoveries _____________ by chance.
A．gained
B．discovered
C．occurred
D．earned
