已知:CrO42﹣和Cr2O72﹣在酸性条件下可以相互转化.
请回答下列问题:
学习历史有一基本结论就是“思想文化是一定现实的反映”。“百家争鸣”学术局面反映的社会现实是( )
You needn't bring any food with you. They will ______ everything for us.