问题描述： （ ）1. How long has he been studying English? _____ he was six years old. A. Since B. For C. At D. On 1个回答 分类：英语 2008-06-28 问题解答： 我来补答 解题思路： since 自······以来 since+时间点 since+句子 for+时间段解题过程：（A ）1. How long has he been studying English? _____ he was six years old. A. Since B. For C. At D. On最终答案：略 展开全文阅读
