来料加工的双方一般是商品买卖关系，而进料加工的双方是委托加工关系。( )
参考答案：错
Let's buy a birthday cake _____ his birthday present _____ the cake shop.[ ]
A.for; for
B.for; on
C.as; in
D.to; in
要使处于不同层次，甚至是互不相关的类可以具有相同的行为采用______。
