Since 1930s the US Army Corps of Engineers has built and operated a string of 8 hydropower stations along the lower Columbia and Snake River and adult and juvenile salmon passages are maintained with various measures.是什么意思_Since 1930s the US Army Corps of Engineers has built and operated a string of 8 hydropower stations along the lower Columbia and Snake River and adult and juvenile salmon passages are maintained with various measures.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句