Past Simple vs. Past Perfect

In the shopping centre, I met a friend who I (see / not) for ages.

(Carly / wash) the dishes when her mum came home?

I went to the library, then I (buy) some milk and went home.

After they (see) the Tower, they (go) to Westminster Abbey.

We ate at a restaurant last night because I (buy / not) anything for dinner.

The thief could walk right into the house because you (lock / not) the door.

When I (get) to the airport I discovered I had forgotten my passport.

When we came back, it was cold in the house because Alice (close / not) the windows.

(why / they / have) dinner before they came to the party?

(he / live) in London before he moved to Glasgow?

We lost the match because we (practise / not) the days before.

(they / book) a room before they went to Dublin?