我感觉有榫舌和凹槽的木材才是环保的。
I suppose the environmental way would be to use tongue-in-groove lumber.
潮汐和洋流雕塑出了沙子，并让水草根植于这片多彩并有凹槽的形状中。
Tides and ocean currents sculpted the sand and seaweed beds into these multicoloured, fluted patterns.
窗口凹槽的设计是为了材料可以来回滑动传递，而不是让你用双手递交。
The window slots were designed for documents to be slid back and forth, not handed.
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