Final answer:
The question suggests that Millie's parents have been deceiving her about her goldfish, possibly replacing it over the years without her knowledge to prevent her from experiencing grief.
Step-by-step explanation:
The question implies that Millie's parents may have been misleading her about the longevity of her goldfish.
The scenario commonly refers to parents telling a child that their pet goldfish is still alive and well when, in fact, it may have been replaced after dying. Parents might choose to do this to shield their child from the grief of losing a pet,
by simply replacing the goldfish without the child's knowledge; this way, the child continues to believe that their original pet has lived an exceptionally long time.