A region of east-central European U.S.S.R. in the Volga River valley. Conquered by the Mongols in the13th and14th centuries,it came under Russian rule in 1552.是什么意思_A region of east-central European U.S.S.R. in the Volga River valley. Conquered by the Mongols in the13th and14th centuries,it came under Russian rule in 1552.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句