Final answer:
The grocery bags from their mom were likely for an event or basic needs, analogous to the wedding gifts Trina receives in the novel 'McTeague' like the unexpected toys from Uncle Oelbermann, highlighting themes of materialism and expectation.
Step-by-step explanation:
The grocery bags that Jackson and Robin received from their mom were likely filled with items in preparation for an event or as a form of assistance for their basic needs. As the context of the question references the various presents Trina and McTeague received for their wedding festivities in the novel McTeague by Frank Norris, it can be surmised that such bags may also represent gifts or necessities intended to be used by Jackson and Robin.
In the provided passage, Trina's anticipation centers on the presents from Uncle Oelbermann, who is rich and has previously shown his favor to her. When the boxes arrive, they contain an unexpected assortment of toys rather than traditional, more practical wedding gifts, which accentuate the novel's themes of materialism and expectation.