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foundation; root; basis; core; fundamentals
root and trunk
この問題は制度の根幹に関わる重要な課題だ。
This problem is an important issue that concerns the foundation of the system.
経済の根幹を支える産業が衰退しつつある。
Industries that support the foundation of the economy are declining.
教育は国家の根幹を成すものである。
Education forms the foundation of a nation.