Choose the correct tense: By the time the guests arrived, we ______ all preparations.
答案解析
核心考点:过去完成时。
解题思路分析:'By the time + 过去时间'需用过去完成时表示动作先后。
选项分析:A. had completed 正确体现动作先后;B. completed 未区分时间顺序;C. have completed 为现在完成时,时态错误;D. will complete 时态矛盾。
易错点提醒:可能忽略'by the time'的时间提示。
正确答案:A