As you may know, Ms. Rothe will be retiring at the end of the year. She has made a great contribution to our company, and will be missed by all her 46 . She has been with the company for fifteen years, 47 up from Sales Assistant to Sales Manager during that time. We will also present her with a small gift. I have asked Mary to organize the 48 for the gift, and she will be coming round with a large brown envelope if you want to make a 49 . The 50 you give is entirely your choice. The leaving party will be after work on December 20th. I look forward to seeing everyone there.

    The ozone layer is a region in Earth’s stratosphere that contains high concentrations of a bluish gas called ozone.Although ozone constitutes only about one-millionth of the 46 gases, it absorbs most of the sun’s ultraviolet radiation. Without the ozone layer, this radiation would destroy all life on the surface of the planet. 

    Ultraviolet radiation creates and perpetuates ozone. Because an ozone molecule is struck by an ultraviolet ray, it falls apart, 47 free oxygen. An oxygen atom can combine with another free oxygen to 48 more ozone, and this cycle absorbs most UV radiation. 

    Some manufactured chemicals interfere with this cycle, thus reducing the amount of ozone in the stratosphere.Among the worst offenders are chlorofluorocarbons (CFCs), usually found in refrigerants and aerosol sprays and now generally 49 due to their harmful effects. Falling ozone levels have caused a thinning of the ozone layer above Antarctica, 50 the ozone hole. The Antarctic ozone hole has increased dramatically in size over the past two decades. A smaller hole over the Arctic is now developing.