第1题: [单项选择]My younger sister ______ the Youth League ______ 1988. A. has joined... in B. has joined... since C. joined... since D. joined... in 参考答案:D 答案解析:[分析] 本题测试点是词汇的用法。join属非持续性动词一类,表示短暂性的动作,在完成时中不能与表示一段时间的状语,如for短语,since短语。因此我们先可将B和C项排除掉。另外如果动词用完成时态,