She ______ (not be) tired if she _____ (go) to bed early.
She wouldn't have been tired if she had gone to bed early.
Mary _____ (not pay) so much for this dress if she _____ (wait) for a sale.
Mary wouldn't have paid so much for this dress if she had waited for a sale.
You ______ (understand) everything if you ____ (listen) to the teacher.
You would have understand everything if you had listened to the teacher.