He pulled himself along the ground using his arms.

pulled 是动词 pull 的过去式，意思是"拉、拖"。 himself 是反身代词，指代主语"他"自己。 along 在这里是介词，表示"沿着...方向"。 pulled himself along 这个短语描述的是"用双臂拖动自己身体前进"的动作。