Final answer:
Without the given text containing references to Mary or the robin, it is not possible to provide a sentence that directly supports the claim that they have met before. The student should check other parts of the text or provide the necessary context for identifying the appropriate supporting detail.
Step-by-step explanation:
The passage that best supports the idea that Mary and the robin have met before is not explicitly provided within the provided excerpts. However, based on the common narrative technique, a sentence that would support this idea might detail a recognition between Mary and the robin, such as the robin showing signs of familiarity or Mary having a sense of recognition upon seeing the robin. Details like these suggest a history or prior encounter between the characters, laying the groundwork for the reader to infer that Mary and the robin have met before. The provided passages do not contain direct references to either Mary or a robin, which are key elements of the original question, indicating that the student may need to look at a different part of the text or provide additional context for the tutor to find a specific sentence that supports the suggested idea.