A field representative to the high production -region in Yutian county, Hebei province was selected and a 70 kg top layer soil sample was taken from the field in June, 1991.是什么意思_A field representative to the high production -region in Yutian county, Hebei province was selected and a 70 kg top layer soil sample was taken from the field in June, 1991.在線翻譯_英語_讀音_用法_例句