Complex sentence: It is difficult for younger children to grasp the idea that objects can be referred to in different ways and that people can have partial knowledge of the different references aaaa "bouncy ball" might also be referred to as a "rubber sphere".
Split into simpler sentences: It is difficult for younger children to grasp the idea that objects can be referred to in different ways and that people can have partial knowledge of the different references. For example, a "bouncy ball" might also be referred to as a "rubber sphere".