The book costs him 50 yuan.(保持原意不变)

问题描述:

The book costs him 50 yuan.(保持原意不变)

It costs hime 50 yuan to buy the book.

The book costs him 50 yuan.(保持原意不变)
He spends 50 yuan on the book
或者
He paid 50 yuan for the book
spend 钱on sth=pay……for=……cost

He pays 50 yuan for the book.
He spends 50 yuan to buy the book.