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单词 tetrahedron 释义 tetrahedron Geom.|ttrhidrn, -hdrn|Pl. -a or -ons. Also 6–9 tetraedron; 6–8 tetra(h)edrum.[ad. late Gr. ά n., prop. neut. of ά adj. four-sided, f. - four + ἕ base.]A solid figure contained by four plane triangular faces, a trian...