单选题 Since Ms. Evans ______ her disappointment regarding the service, the store manager has been careful to keep his eyes on the staff"s behavior.
【正确答案】 D
【答案解析】[解析] 语法：时态
1．这是一道时态选择题。选项均为动词的不同时态。
2．主句动词为现在完成时(has been)，since引导的从句应使用过去时。