這是ETS出的托福閱讀geolog and landscape其中一段
Under very cold conditions,rock can be shattered by ice and frost.Glaciers may form in permanently cold areas,and these slowly moving masses of ice cut out valleys,carrying with them huge quantities of eroded rock debris
請問斜線部分是屬同位語嗎?
carrying所省略的主詞是 glacier or these slowly moving masses of ice
煩請高手替小弟解惑一下...