随着化石燃料开采变得更加困难且昂贵，可再生能源的成本正在下降。
As extracting fossil fuels becomes more difficult and expensive, the cost of renewable energy is falling.
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falling英 /ˈfɔːlɪŋ/|美 /ˈfɔlɪŋ/
解释
falling 是动词 fall 的现在分词形式，fall 本意是“落下、下降”，这里指成本“下降、降低”。
As extracting fossil fuels becomes more difficult and expensive, the cost of renewable energy is falling.
falling 是动词 fall 的现在分词形式，fall 本意是“落下、下降”，这里指成本“下降、降低”。