肾脏分泌肾素的主要部位是：（）
A.致密斑
B.球旁细胞
C.间质细胞
D.肾小管细胞
E.肾小球毛细血管内皮细胞
参考答案：B
People often have this belief _______economic development is bad for the environment, but this does not have to be true.
A．what
B．which
C．that
D．when
大型露天矿的服务年限应为多少年？
