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滋    蔓    难    图    本指野草滋生，难以消除。后以之比喻势力扩大了再要消灭它就很困难。

滋蔓难图，成语，比喻势力扩大了再要消灭就很困难。

It will be too late to deal with an enemy if he is allowed to grow in strength.

滋蔓难图