My mother bought me a red purse.改为被动语态.

My mother bought me a red purse.
改为被动语态：
这是一个带有双宾语的句型,其变换方式有两种.第一种方式通常是把表示物的直接宾语改为被动语态的主语,即.A red purse was bought for me by my mother.；第二种方式是把表示人的间接宾语改为被动语态的主语,即 I was bought a red purse by my mother.
注意：带双宾语的动词如果把表示人的宾语放在后面时需要在人和物之间加一个介词（表方向用to,表目的用for).如：
I gave him a book.=I gave a book to him.
I bought him a book.=I bought a book for him.