After our first echelon was 250 or 300 kilometers ahead,the second and third echelons still had to wipe out enemy troops left behind.是什么意思_After our first echelon was 250 or 300 kilometers ahead,the second and third echelons still had to wipe out enemy troops left behind.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句