be made of 与be made from 的区别。

be made of 是指由什么组成，通常指物理变化
比如：The chair is made of wood.

be made from 是指由什么转化而成，通常指化学变化
比如：The gas is made from petroleum.

be made of “由…制成”，制成品能看出原材料
be made from 意思也是“由…制成”，但制成品不能看出原材料

be made from
由...所做成的(用于原材料不易看出的场合)

be made of
用...造成(用于原材料显而易见的场合)