托福托福【阶段测试-4】-2017服务一体化阅读The word virtually in the passage is closest in meaning to 答案解析【小站备考】

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.

Among the most elegant and enduring of Roman structures based on the arch is the Pont du Gard at Nimes, France, built about 15 c.e. when the empire was nearing its farthest expansion. At this time, industry, commerce, and agriculture were at their peak. Roman engineering was applied to an ambitious system of public-works projects, not just in Italy but in the outlying areas as well. The Pont du Gard functioned as an aqueduct, a structure meant to trans- port water, and its lower level served as a footbridge across the river. That it stands today virtually intact after nearly two thousand years (and is crossed by cyclists on the route of the famous Tour de France bicycle race) testifies to the Romans’ brilliant engineering skills. Visually, the Pont du Gard exemplifies the best qualities of arch construction. Solid and heavy, obviously durable, it is shot through with open spaces that make it seem light and its weight-bearing capabilities effortless.

When the arch is extended in depth—when it is, in reality, many arches placed flush one behind the other—the result is called a barrel vault. This vault construction makes it possible to create large interior spaces. The Romans made great use of the barrel vault, but for its finest expression we look many hundreds of years later, to the churches of the Middle Ages.

The church of Sainte-Foy, in the French city of Conques, is an example of the style prevalent throughout Western Europe from about 1050 to 1200—a style known as Romanesque. Romanesque builders adopted the old Roman forms of round arch and barrel vault so as to add height to their churches. Until this period most churches had beamed wooden roofs, which not only posed a threat of fire but also limited the height to which architects could aspire. With the stone barrel vault, they could achieve the soaring, majestic space we see in the nave of Sainte-Foy.

Pointed Arch and VaultWhile the round arch and vault of the Romanesque era solved many problems and made many things possible, they nevertheless had certain drawbacks. For one thing, a round arch, to be stable, must be a semicircle; therefore, the height of the arch is limited by its width. Two other difficulties were weight and darkness. Barrel vaults are both literally and visually heavy, calling for huge masses of stone to maintain their structural stability. Also, the builders who constructed them dared not make light-admitting openings in or around them, for fear the arches and vaults would collapse, and so the interiors of Romanesque buildings tend to be dark. The Gothic period in Europe, which followed the Romanesque, solved these problems with the pointed arch.

The pointed arch, while seemingly not very different from the round one, offers many advantages. Because the sides arc up to a point, weight is channeled down to the ground at a steeper angle, and therefore the arch can be taller. The vault constructed from such an arch also can be much taller than a barrel vault. Architects of the Gothic period found they did not need heavy masses of material throughout the curve of the vault, as long as the major points of intersection were reinforced. Glossarynave: the long central area in a church with aisles on each side

托福【阶段测试-4】-2017服务一体化 The word virtually in the passage is closest in meaning to

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