已知函数的两个极值点分别为，且，点表示的平面区域为，若函数（）的图象上存在区域内的点，则实数的取值范围是（ ）
______ along with host families, I believe, language travel students are likely to get enough language practice.
Today we have chat rooms, text messages and email, but we seem _______ the art of communicating face-to-face.
_________ to too much sunlight will do harm to your skin.
（）There is no greater pleasure than lying on my back in the middle of the grassland, _____at the night sky.
__________ the program , they have to stay there for another two weeks.
的两个极值点分别为
，且
，点
表示的平面区域为
，若函数
（
）的图象上存在区域
内的点，则实数
的取值范围是（ ）
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