2022年自考《英语（二）》模拟题（18）

Although the weather is very hot now,the carnival of ice and snow is getting closer.The preparation work for Beijing Winter Olympic Games,which are expected to begin on Feb 4,2022,has entered its final stage.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 difference.“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 US 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 more pure the water is,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(CO2)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 Organizing Committee of the Beijing Winter Olympic Games.