车站主体结构防水混凝土一般要求：抗渗等级（），其余附属结构混凝土抗渗等级不得小于()。
参考答案：S10、S8
—Did you see Mr Smith when you were in France?
—No , when I _____ France, he had gone to China .[ ]
A. had arrived to
B. arrived to
C. had got to
D. got to
有营养性巨幼细胞贫血可疑时，最适合的确诊方法是()
A．血清铁测定
B．血浆维生素B12测定
C．血浆叶酸测定
D．血象检查
E．骨髓象检查
