At its center you will find a double spiral staircase that was said to be designed by Leonardo da Vinci.
在它的中央你可以看到一座据说是达芬奇设计的双旋楼梯。
DNA is the basis of all life on earth. It has a double helixstructure， like a spiral staircase.//
DNA 是地球上所有生命的基础，它有着像螺旋式楼梯一样的双螺旋结构。
DNA is a double stranded molecule shaped like a spiral staircase.
DNA是一种像螺旋阶梯样形状的双链分子。
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