而对天文观察者来说，它意味着夏季的标志—夏季大三角（在夏季的东南方高空里由天琴座的织女星、天鹅座的天津四及天鹰座的牛郎星组成的三角形）的退去和预示着秋季的星座的到来。
For skywatchers it means the passing of the season's trademark Summer Triangle of stars and the arrival of the autumn constellations.
每一个理想的多面体是依次由三角形组成。
Each of these perfect polyhedra would be in turn composed of triangles.
在晶体中观察到多个层错和一个由两个层错三角形组成的层错四面体。
Several stacking faults and a tetrahedron composed of two stacking faults in triangular were observed within the crystal.
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