题目

读图，图中甲山地的地质构造属于                                       A.背斜构造               B.向斜构造 C.断层构造               D.板块构造   答案：B甲处岩层向下弯曲，所以为向斜构造。China _____ the WTO in 2001. [     ]A. joinB. joinsC. joinedD. joining