1 . In January, 2021, the ice-making work on the ”Ice Ribbon“, a landmark venue for the Beijing Winter Olympics, was completed.

In the Winter Olympics, where races can be won or lost by a small time gap, tiny imperfections in the ice can make all the differences. ”It’s not just a hunk of ice like you’d normally think of, like ice cubes sitting in your freezer,“ told Kenneth Golden, a U. S. mathematician who studies the structures of ice. ”It’s a much more fascinating and complex substance than people would normally think.“

The first step for building any ice rink is to purify the water to remove dissolved solids like salts and minerals. Such impurities don’t fit in the regular hexagonal(六边形的)structure of ice that forms as water freezes. The purer the water, the more consistent the ice surface.

In addition to the need for excellence in the raw materials of ice-making, technology is also very important, As one of the most advanced technologies for winter sports venues, a carbon dioxide cooling technology has been applied on a large scale for the Beijing Winter Olympic Games. CO₂ , is not new when it comes to ice-making. However, it has been gradually replaced by the man-made refrigerant, like Freon.

With increasing attention toward climate change, the old refrigerant has come into use again. As an element of the atmosphere, CO₂, doesn’t damage the ozone layer. Although CO₂ is a greenhouse gas, its greenhouse effect is much lower than that of other synthetic refrigerants. The Winter Olympics venues adopted CO₂ instead of Freon as a refrigerant in ice-making, which will reduce carbon dioxide emissions greatly.

”We believe these technological innovations will bring Beijing 2022 to spectators all over the world in a more impressive way.“ told Gao Bo from the Media Operations Department of the Beijing Organizing Committee for the 2022 Olympic and Paralympic Winter Games.

1. What is the result of impurities in water for ice-making?

A．The water isn’t able to freeze completely.

B．The quality of the ice will be affected.

C．The ice surface will be more consistent.

D．It’s likely for athletes to fall on the ice.

2. Why has CO₂ cooling technology been applied for the Winter Olympic Games?

A．It’s the most advanced technology for ice-making.

B．CO2 is more efficient than other refrigerants.

C．CO2 is more environmentally friendly than Freon.

D．CO2 has already existed in the atmosphere.

3. What is Gao Bo’s attitude to CO₂ being applied to ice-making?

A．Unclear.

B．Opposed.

C．Doubtful.

D．Favorable.

4. Which of the following is a suitable title for the text?

A．The Beijing Winter Olympic Games Are Coming

B．Beneath Olympic Ice

C．The Use of Refrigerants in Olympic Games

D．The Structure of Ice