Which one of the underlined words or phrases is INCORRECT? I don't had enough money to buy a bus ticket, so I'II…

Which sentence has the CORRECT WORD ORDER?

When you were in Paris last year, ----------- the Eiffel Tower?

Mary ...... on her term paper when the phone rang.

If I ........... there, I................... said something to the manager.

When you go to the bookstore today,................ you buy a notepad for me, please?