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.

(1). How long did it take China to develop the CO₂ direct cooling technology?

A. 18 months.B. 100 weeks.C. 15 days.D. 7 years.

(2). The writer writes Para. 3 to show ________.

A. why the CO₂ goes into another circle

B. how the new ice-making technology helped

C. how sporting places used the new technology

D. why the liquid CO₂ runs through the net of tubes

(3). According to the passage, we can infer(推断) that ________.

A. all the buildings will be built with glass walls in the near future

B. the CO₂ direct cooling technology may be widely used in the world

C. the high-pressure liquid CO₂ will totally take the place of R507 soon

D. no new standards in green technologies may be set after the Olympics

(4). Which of the following can be the best title for the passage?

A. A New Green Ice-making Technology

B. Green Technologies Used in Sports

C. A Shared Future of Green Development

D. The Green Beijing Winter Olympics