be made of和be made from有什么区别

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.

be made of和be made from都可以表示某物体由什么材料制成，它们的区别如下：
当构成物体的材料从物体外观上能看出来的时候，就可以用be made of，在口语中也可以用be made out of来表示，如：
The salad is made of tomatoes and cucumber.
This kind of wood, of which this desk is made, is very hard.
I made my bicycle out of four old ones.
Coins are made out of metal.
The book is made of paper.
当肉眼看不出来构成物体的材料的时候，要用be made from，如：
Wine is made from grapes.
This kind of wood, from which this kind of paper is made, is very hard.
Bread is made from flour.

be made of看得出原材料。只发生了物理变化。

be made from看不出原材料。发生了化学变化。

be made of表示由成品能看出原材料,也就是物理变化.
例 The table is made of wood.桌子是由木头制成的.
be made from则表示由成品看不出原材料.也就是化学变化.
例 Paper is made from wood.纸是由木头制成的.

be made of 原材料可以看出来，be made from 原材料看不出来。