胡 * * * * 指出，党的先进性和党的执政地位都不是一劳永逸、一成不变的，过去先进不等于现在先进，现在先进不等于永远先进；过去拥有不等于现在拥有，现在拥有不等于永远拥有。胡 * * * * 还指出，不动摇、不懈怠、不折腾，坚定不移地推进改革开放，坚定不移地走中国特色社会主义道路。阅读材料回答：

（1）请你回答发展的实质是什么？

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（2）请运用发展观的知识分析回答：为什么说“党的先进性和党的执政地位都不是一劳永逸、一成不变的”？

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（3）请运用生活与哲学的知识分析回答：坚持改革开放“不动摇、不懈怠、不折腾”的哲学依据。

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食管癌影像学表现（）。

A.食管呈现细线状狭窄，壁光滑

B.食管黏膜呈串球样改变

C.食管腔外压迫，黏膜光滑完整

D.食管狭窄，黏膜破坏，中断

E.食管扩张，食管下段呈光滑的鸟嘴状狭窄