miércoles, 13 de noviembre de 2013

Textos habilitación tercero

The Germans were the first people to celebrate children´s birthdays. Before that, only kings had birthday celebrations. Maybe that is why we sometimes wear paper crowns at birthday parties. The ancient Greeks put candles on round cakes to make it appear like the moon. Nowadays, it is the tradition to put candles on the cake. The person who is celebrating the birthday, blows out the candles and makes a wish.

The Ozone Layer
Ozone es a special type of gas; it forms a layer in the atmosphere that protects us form most of the sun´s ultraviolet light rays. Too much ultraviolet light can damage our skin. It also affects the weather and the growth of crops and other plant life. Ozone holes are over the poles. They are big areas of the atmosphere where the ozone layer is getting very thin. Scientists discovered that the ozone layer is being destroyed by chemicals called CFCs. These substances are released into the atmosphere by some refrigerators and air-conditioning systems, foam packaging such as fast food cartons, and some sprays

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