Then, the person who has left the room comes back in and
asks each student in turn only one question and the full question is 'What would
you have done if this had happened?'
And each student in turn answers in a full sentence for example, 'If this had
happened, I would have bought some flowers'
Now, they mustn't mention the names of anyone involved because at the end the student who is guessing has to work out what happened to whom and, if they can't, you can go round again with new answers.
[As this is for speaking practice, the students should use
the contracted form for the conditional grammar - 'If this'd happened, I'd 've
bought some flowers.']
(http://www.teachingenglish.org.uk/try/speaktry/speaking_activities.shtml#task)