Final answer:
The fly in the ointment of Timmy's friendship with Rollo refers to a problem or issue that caused a disruption or strain in their relationship. It could be something that affected their trust, communication, or shared experiences.
Step-by-step explanation:
The fly in the ointment of Timmy's friendship with Rollo refers to a problem or issue that caused a disruption or strain in their relationship.
It could be something that affected their trust, communication, or shared experiences. For example, the fly in the ointment could be a disagreement, a secret betrayal, or a misunderstanding that occurred between them.