--- title: Bridges and skyscrapers — a lesson of Mova's school · trees and pragmatics description: «Bridges and skyscrapers», a lesson of the technology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Every bridge and every building has one job: to carry its own weight, and the weight of everything on it, safely down into the ground. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Technology](https://md.mova.elamur.ai/free/en/corpora/school/technology/) / Bridges and skyscrapers # Bridges and skyscrapers Lesson 30 of the technology course of Mova's primary school: 23 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/technology/30-bridges-and-skyscrapers/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/0/) — Every bridge and every building has one job: to carry its own weight, and the weight of everything on it, safely down into the ground. - [1](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/1/) — Engineers choose a shape that does this best for each place. - [2](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/2/) — A beam bridge is a plank resting on supports. - [3](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/3/) — An arch pushes its weight sideways and down into the ground at its ends, so its stones are squeezed together and hold each other tight. - [4](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/4/) — A suspension bridge hangs its road from huge cables slung over tall towers. - [5](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/5/) — Lie a ruler across two books and press the middle: it bends. - [6](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/6/) — Curve a strip of card into an arch between the books, with its ends held against them, and it carries far more. - [7](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/7/) — Shape, not just material, makes things strong. - [8](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/8/) — A skyscraper is a strong steel or concrete core and frame standing on deep foundations; its glass walls are only a skin. - [9](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/9/) — Tall buildings even sway a little in the wind on purpose, because a building that can bend a little does not snap. - [10](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/10/) — A suspension bridge hangs its road from smaller cables attached to huge main cables, which run over tall towers and are anchored in rock or concrete at the ends. - [12](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/12/) — A beam bridge rests on supports, while an arch pushes the weight sideways and down into the ground; Roman stone arch bridges still stand after about 2,000 years. - [13](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/13/) — Lifting and swing bridges use motors and counterweights to lift or turn so tall ships can pass; Tower Bridge in London has opened for ships since 1894. - [14](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/14/) — Never stand on a bridge that is about to open. - [15](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/15/) — Bridges grow longer in heat and shorter in cold, and expansion joints, metal teeth or gaps, let them move, since without them a bridge swelling in the heat would push hard against its ends and could crack or buckle; long bridges can change length by tens of centimetres between winter and summer. - [16](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/16/) — A skyscraper's strong steel or concrete core and frame carry the weight down to deep foundations; the walls are just a skin. - [17](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/17/) — The Burj Khalifa in Dubai, over 800 metres tall, is the tallest building in the world for now. - [18](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/18/) — Tall buildings bend a little in the wind; some have huge weights near the top that swing to calm the movement, and Taipei 101 has a giant golden ball weighing over 600 tonnes. - [19](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/19/) — Skyscraper windows are cleaned from a cradle that hangs from rails on the roof and moves down the building, and some buildings use robot cleaners. - [20](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/20/) — Earthquake-proof buildings can stand on rubber and steel pads or springs, so the ground shakes while the building moves less; in an earthquake, drop, cover and hold on. - [21](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/21/) — Scaffolding is a temporary frame of steel poles and boards clamped together by hand by scaffolders, with diagonal braces so it does not wobble; never climb scaffolding. - [22](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/22/) — A house's foundations are concrete under the walls that spread its weight over the ground, so it does not sink; houses on clay can move a little in very dry summers, because the clay shrinks. - [23](https://md.mova.elamur.ai/free/en/corpora/school/technology/30-bridges-and-skyscrapers/23/) — A suspension bridge usually has 2 tall towers. - ← previous: [Tunnels and what lies under the street](https://md.mova.elamur.ai/free/en/corpora/school/technology/29-tunnels-and-under-the-street/) - next →: [Roads and road signs](https://md.mova.elamur.ai/free/en/corpora/school/technology/31-roads-and-road-signs/) - ↑ back to [Technology](https://md.mova.elamur.ai/free/en/corpora/school/technology/)