what was the lies in act one?

Jack lies to cover up his double life. A simple white lie that he doesn’t know anyone named "Cecily" gets him into an incredibly messy situation. When he’s forced to admit he does know a "Cecily," he tries to pass her off as his aunt. But Algy, a fellow Bunburyist, eventually sniffs it all out and forces Jack to confess. What is most surprising is that Jack seems to have no shame about the lies he’s been feeding to Algernon for years.