be made of和be made from都表示“由……制成”,主语为制成品.
1.be made of 表示制成成品后,仍可看出原材料是什么,保留原材料的质和形状,制作过程仅发生物理变化.如：
The kite is made of paper．风筝是用纸做的.
2.be made from 表示制成的东西完全失去了原材料的外形或特征,或原材料在制作过程中发生化学变化,在成品中已无法辨认.如：
The paper is made from wood．纸是木头做的.
Butter is made from milk．黄油是从牛奶中提炼出来的.