thereby hangs a tale;there are wheels within wheels; there is far (/much)more to it than that C/than appears/than meets the eye) ; something (more) behind all this
❍ 他说 “刘军长的来电，你们看过了吗？其中～！ ……”(杜鹏程 《保卫延安》433) “Have you all seen General Lifts telegram?”he asked. “Quite a dissertation? …”/我觉得这件事背后可能～。I am inclined to think there i s something more behind all this.
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形容言谈或文章十分令人费解。hangs a tale,there is much finesse in ...,there is sth. behind all this, There is more to it than meets the eye.