Study the dialogue and answer the question
Didi: (tap on someone’s shoulder) Where have you been? I was looking for you.
Someone: (turn around) Excuse me, Do I know you?
Didi: Oh, I thought you were my friend.
Someone: Sorry, I don’t think we have met before.
Didi: God, what an embarrassment! I’m really sorry.
Someone: No problem.
The sentence that expresses an embarrassment is ….