What is the rule about splitting infinitives? how would you rewrite the quote above based on this rule?

(1) fire extended humans’ geographical boundaries by allowing them to travel into regions that were previously too cold to explore. (2) it also kept predators away, allowing early humans to sleep securely. (3) fire, in fact, has been a significant factor in human development and progress in many ways. (4) other obvious benefits of fire are its uses in cooking and in hunting. (5) probably even more important, however, is that learning to control fire allowed people to change the very rhythm of their lives. (6) before fire, the human daily cycle coincided with the rising and setting of the sun. (7) with fire, though, humans gained time to think and talk about the day’s events and to prepare strategies for coping with tomorrow. the sentence that expresses the main idea is: (type the number of the sentence. then click “go.”)

When i was young enough to still spend a long time buttoning my shoes in the morning, i'd listen toward the hall: daddy upstairs was shaving, in the bathroom, and mother downstairs was frying the bacon. they would begin whispering back and forth to each other up and down the stairwell. my father would whistle his phrase, my mother would try to whistle, then hum hers backi drew my buttonhook in and out and listened to it -know it was "the merry widow." the difference was, their song almost floated with laughter. how different from the record, which growled from the beginning, as if the victrola were only slowly being wound up. they kept it running between them, up and down the stairs where i was now just about ready to run clattering down and show them my shoes. what is the effect of the parallelism used in the above excerpt? it establishes the rhythm of a duet to echo the song. it expresses the same ideas. it mirrors opposite ideas. it is a paradox.

Me which theme is developed by the changing relationship between the narrator and his daughter in this excerpt ? as she grew older, she spent more of her time with girls. so much time indeed did she spend with them that she came no more, as she used to do, to her father’s room. i was scarcely on speaking terms with her. when mini and her father stop communicating, it develops the theme that children should not speak unless spoken to. as mini becomes more independent, it develops the theme that parents must learn to let go as their children grow up. as mini spends more time with friends, it develops the theme that young people are more influenced by peers than by parents. when mini and her father see each other far less often, it develops the theme that absence makes the heart grow fonder.