以下不属于按水泥用途和性能分类的是（）。
A.通用水泥
B.普通硅酸盐水泥
C.特性水泥
参考答案：B
________, Mr. Wells is scarcely in sympathy with the working class.
A．Although he is a socialist
B．Even if he is a socialist
C．Being a socialist
D．Since he is a socialist
农业技术经济学的基本理论是什么？
