The source of much of this chlorine is chlorofluorocarbons (CFCs) that were widely used in many products over the last century.
氯的来源是来自于含氯氟烃，这个物质我们在上个世纪中用于多种产品里面。
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Our use of ozone-depleting substances such as chlorofluorocarbons (CFCs) had torn a hole in the ozone layer that protects us from the sun's harmful ultraviolet radiation.