Present Perfect vs Past simple

I ______ yet where to go this weekend.

Mary ______ school 10 years ago.

When_____ you come?

He _____ a letter and now he is going to send it.

John _______ yet.

Clara ____ never_____ abroad.

John _____ his bag in the library last Monday.

Harry and Jane ______ new TV set and now are enjoying a film.

His grandfather _____ when he was a child.

Last weekend they _____ to the sea.