Because it not only gets paid by other countries (for importing their waste) but also turns the waste into energy.
题意:
为什么作者说瑞典通过进口垃圾创造了一个双赢的局面?
根据第三段,第二句Sweden not only gets paid by other countries but also changes the waste into energy in Sweden,which provides electricity and heating for so many homes.瑞典不仅得到其他国家的补贴,还把垃圾转化为能源,为许多家庭提供电力和供暖。可知,作者说瑞典通过进口垃圾创造了一个双赢的局面的原因是瑞典不仅得到其他国家的补贴,还把垃圾转化为能源。