I bought this book
Compré este libro el otro día.
I bought this book the other day.
That's why I bought this book.
Compré este libro hace tres días.
I bought this book three days ago.
I didn't buy this book.
Compré este libro donde Kakuzen.
I bought this book at Kakuzen's.
I bought this book for myself.
Compré este libro en la librería frente a la estación.
I bought this book at the bookstore across from the station.
Compré este libro para mí, no para mi esposa.
I bought this book for myself, not for my wife.