Much of the world's great architecture has been constructed of stone because of its beauty, permanence, and availability. In the past, whole cities grew from the arduous task of cutting and piling stone upon. Some of the world's finest stone architecture can be seen in the ruins of the ancient Inca city of Machu Picchu high in the eastern Andes Mountains of Peru. The doorways and windows are made possible by placing over the open spaces thick stone beams that support the weight from above. A structural invention had to be made before the physical limitations of stone could be overcome and new architectural forms could be created. That invention was the arch, a curved structure originally made of separate stone or brick segments. The arch was used by the early cultures of the Mediterranean area chiefly for underground drains, but it was the Romans who first developed and used the arch extensively in above ground structures. Roman builders perfected the semicircular arch made of separate blocks of stone. As a method of spanning space, the arch can support greater weight than a horizontal beam. It works in compression to divert the weight above it out to the sides, where the weight is borne by the vertical elements on either side of the arch. The arch is among the many important structural breakthroughs that have characterized architecture throughout the centuries.
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12. According to paragraph 6, which of the following statements is true of the arch?
A. The Romans were the first people to use the stone arch.---错误，不是first ，是 The arch was used by the early cultures of the Mediterranean area
B. The invention of the arch allowed new architectural forms to be developed.
A structural invention had to be made before the physical limitations could be overcome and new architectural forms could be created---因为拱的诞生，所以解决了物理限制和创造了新建筑形式
C. The arch worked by distributing the structural load of a building toward the center of the arch.----错误，不是将力量分配到中间，而是两边。
distributing 分配
arch works in compression to divert the weight out to the sides
D. The Romans followed earlier practices in their use of arches.--错误，罗马人没有沿袭前人做法
