Mum，you really need to have a rest！You in the kitchen ever since you came back home three hours ago.
A. had worked
B. were working
C. have been working
D. worked
网友回答
A. had worked
B. were working
(答案→)C. have been working
D. worked
解析：
句意为：妈妈你真的需要休息了！从你三小时前回到家里，你就一直在厨房干活。强调从过去开始的某一动作一直延续至今并仍在进行时，用现在完成进行时。