be made of vs be made from

be made of ：指能看得出来啥做的，比如桌子是木头做的，电话是塑料做的等等；This kind of cloth is made of wool. 这种布料是羊毛的。All the furniture is made of wood. 所有的家具都是木头做的。

be made from ：看不出原材料，由from比of读音响亮，可以理解为 from 比 of 更强调“啥做的”；The cake is made from flour, butter, sugar and eggs. 蛋糕是由面粉、黄油、蔗糖和鸡蛋做的。This kind of towel is made of bamboo. 这种毛巾是竹子制作的