What are pears and begonia in a pear flower?

Pear flower refers to the old man, and Haitang refers to the girl. Nowadays, "a pear hits a begonia" is often used to describe an old cow who eats young grass and forgets his age. There is a novel called Lolita abroad, which was originally banned, but now there is no way out. The title translated into Chinese is "A Pear Blossom Over a Begonia", which tells the story of uncle and Lolita's love.