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The child is a reality in himself, and not merely a transitional being.
孩子本身就是一个现实,而不仅仅是一个过渡性的存在。
For systems, the analogue of a face-lift is to add to the control graph an edge that creates a cycle, not just an additional node.
数学不是一项观赏性运动;要理解它,必须积极参与其中。