单选题3. The salesperson ______ have been any nicer; she gift-wrapped all my purchases and even helped bring everything out to my car.
【正确答案】
D
【答案解析】 选项A错误，如果填shouldn't，那么售货员对顾客友善反而成了错误的。选项B错误，填wouldn't则意思是售货员不愿意变得更友善一些。选项C错误，填might则意思是售货员可能变得友善些，但后半句说明售货员对顾客很好。选项D是最佳答案，couldn't have been any nicer意思是“售货员(对顾客)好得不能再好了”。