阅读理解The Beijing 2022 Winter Olympics was a great success. China has kept the promise to hold a green Olympics. Many green actions made it possible, like providing environmentally friendly smart beds, using new energy(能源) cars, supporting sporting places with 100% clean energy and reusing rain and snow water.
Take making ice as an example. China didn't use R507, a common material to make ice, because it isn't friendly enough to the environment. Through 18 months' hard work, China independently developed the CO2 direct cooling technology.
A net of tubes runs under the ice. High-pressure liquid(液态) CO2 goes through them to create heat(热) exchange. The CO2 evaporates(蒸发) under the ice surface. The evaporation takes in heat and turns water on the surface into ice. And the CO2 goes into another circle. This technology helps to make ice better and faster. And above all, it is much greener because there's no new CO2 produced. Among all the 15 ice sporting places in the Winter Olympics, 7 used the CO2 direct cooling technology to make ice. As a result, much less pollution was caused.
Beijing did so much more to save energy. Beijing built the new sporting places with green materials. As for the old ones, Beijing used new glass walls to take the place of traditional walls to let more natural light in. 70% of the waste heat was also reused to keep warm and dry. And a large number of new energy cars were used at the Beijing 2022 Winter Olympics.
The Beijing 2022 Winter Olympics is the first to truly achieve carbon neutrality(碳中和), and it has set new standards in green technologies. Some newspapers say China has set an example for the world in environmental protection and green development.
