4周搞定2000+托福核心词
楔形的
wedge-shaped
常考释义
adj. 楔形的
In the wedge-shaped plateau are great old cities supported by rich farmlands.
在梯形状的高地上,有肥沃农田赡养的著名古城。
Although the round arch was used by the ancient peoples of Mesopotamia several centuries before our common era, it was most fully developed by the Romans, who perfected the form in the 2nd century b.c.e. The arch has many virtues. In addition to being an attractive form, it enables the architect to open up fairly large spaces in a wall without risking the building's structural soundness. These spaces admit light, reduce the weight of the walls, and decrease the amount of material needed. As utilized by the Romans, the arch is a perfect semicircle, although it may seem elongated if it rests on columns. It is constructed from wedge-shaped pieces of stone that meet at an angle always perpendicular to the curve of the arch. Because of tensions and compressions inherent in the form, the arch is stable only when it is complete, when the topmost stone, the keystone, has been set in place. For this reason an arch under construction must be supported from below, usually by a wooden framework.
虽然圆拱在公元前几个世纪以前，就被美索不达米亚的古老民族使用，但是是罗马人让圆拱得到了充分的发展，罗马人在公元前二世纪使圆拱这一建筑形式得到完善。拱形有很多的优点，除了有吸引力之外，建筑师还能利用拱形，在不危及到建筑结构安全性的情况下，扩展出相当大的空间。这些空间可以增加采光度，减少墙面压力，并减少所需要的建筑用材。正如罗马人所利用的那样，拱形是一个完美的半圆，虽然如果它被建造在柱形上的话，它看起来似乎像是被拉长了。它是由楔形的石块组成的，这些楔形石块与拱形的曲线保持垂直。因为这种建筑形式向来张力大且紧实，所以拱形只有在当它是完整的时候，当最顶端的那块石头——拱心石放置到位的时候才能保持稳固。因此，建造拱形建筑时，下方必须要有支撑，通常是用木架来支撑的。
来源于：阅读托福【阶段测试-4】-2017服务一体化 P3以上图片仅供学习交流使用，版权归原作者所有，如有侵权，请与我方联系
