6. ‘Did you know that Sarah was an Olympic athlete?’
‘No! She’s such a …..’
a. little bird - Wrong, Sarah did not tell someone a secret
b. dark horse - Correct, Sarah has a hidden and unusual past
c. cat in a bag - Wrong, when you let the cat out of the bag you reveal a secret
d. skeleton in her closet - Wrong, a skeleton in your closet is a shameful thing