---Would you please tell us something about the Group of Eight(G8)?

---Well, G8 is an international organization________the richest countries in the world, five of which are quite small and two of which are island states.

A．is consisted of

B．consisting of

C．consists of

D．consisted of

对于挡水建筑物有时将坝轴线布置成折线，其主要考虑的理由是（）。

A.可使坝轴线最短

B.可使坝身体积最小

C.对建筑物的受力状态有利

D.受地质和地形条件的限制