学员疑问：老师，这个题为什么选D？

She was complaining that the doctor was ______ too much for the treatment he was giving her.

A. expending         B. offering                    C. costing                     D. charging

老师解答： 由句中关键词“She was complaining她抱怨”与“the treatment治疗”的对应，可知构成固定搭配“charge for sth. 向……收费”的D项正确。

点评分析： 词汇题做的时候，要根据空格前面的词推测空格处单词的词性以及习惯性用法。