—Catherine, I have cleaned the room for you.
— Thanks. You _______ it. I could manage it myself.
A:needn't have done
B:needn't do
C:mustn't do
D:shouldn't have done
下图反映了我国哪项金属冶炼技术的进步的是( )
阅读下面一首诗,完成题目。 宿云梦馆(欧阳修) 北雁来时岁已昏,私书归梦杳难分。 井桐叶落池荷尽,一夜西窗雨不闻。