Choose the correct option.

0 By the time I arrived / had arrived, my friends already left / had already left the exhibition.
1 After I saw / had seen the painting, I knew / had known I had to buy it.
2 Fortunately, I took / had taken the photos before it started/had started raining.
3 I already sent / had already sent the invitations when I realised/had realised I hadn't signed them.
4 I never gave/had never given a speech before I spoke / had spoken at the Modern Art gallery.
5 Marie and David became / had become world-famous photographers after they were / had been in a programme on Discovery Channel.