新编英语教程6Unit Three.ppt

Unit ThreeWalls and Barriers墙与屏障 Eugene Raskin Pre-Class Work A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall outlines a building and supports its superstructure, separates space in buildings into rooms, or protects or outlines a space in the open air. There are three principal types of structural walls: building walls, exterior boundary walls, and retaining walls. 1. Building Walls have one main purpose: to support roofs and ceilings. 2. Boundary Walls (Protective Walls) They include privacy walls, boundary-marking walls on property, and town walls. Example: The Great Wall of China The Great Wall of China 3. Separation walls Some walls are designed to formally separate one population from another. A example was the Berlin Wall, which divided East and West Berlin. Berlin Wall View in 1986 from the west side of graffiti art on the wall’s infamous “death strip” An old Italian wall surrounded by flowers 4. Retaining walls 5. Shared walls 6. Portable walls Walls in popular culture In culture a wall normally means a barrier stopping progress or entry. For instance the progressive rock band Pink Floyd have a concept album called The Wall. This Wall is not real, but a metaphor for social barring. Another common usage is as a communal surface to write upon. For instance the social networking site Facebook uses a wall to log the scrawls of friends. Users have gone on to create more advanced versions of the original wall, such as the application SuperWall. I. Library Work The following are some pictures of the great buildings in the history all over the world, which help to illustrate different architectural styles and designs. Saint Paul’s Cathedral  London, England, United Kingdom, 1675 to 1710 Construction System: masonry, brick, timber, and cut stone The White House Washington, D.C., 1793 to 1801 Construction System: cut stone bearing masonry Empire State Building New Y