题目

You told me you had ________ (deal) with these letters. Why are they still here? 答案：【答案】dealt【解析】句意：你告诉我你已经处理过这些信了。他们为什么还在这里？根据“You told me you had…”中的told可知，从句应该用过去完成时，其结构是“助动词had+动词的过去分词”；deal的过去分词为dealt。故填dealt。先化简，再求值： ，其中a=-5，b=4．