问题描述: our country _the WTO for many years.A has joined C:has been in 1个回答 分类:英语 2014-11-26 问题解答: 我来补答 选B,因为后面的for many yeas 是持续的时间,所以必须用延续性动词,而A是非延续的. 展开全文阅读