求大神帮改被动语态,

People are spending more money on food now.
More money is being spent on food by people now.
He finished writing the book at last.
The book was finished writing by him at last.
We can't exchange the articles bought during the sale.
The articles bought during the sale can't be exchanged by us.
We have paid much attention to the news about MH703.
The news about MH703 have been paid much attention to by us.
He addressed a letter to his wife on his way to work.
A letter was addressed to his wife by him on his way to work.