What is the controlling idea in the paragraph -   1my introduction to school was unpleasant at best.  2my first-grade teacher's name was miss spencer, and was she ever mean.  3she pulled her hair back from her face and put it in a tight bun.  4 her mouth was down-turned, and she had permanent creases between her eyes from scowling all the time.  5the classroom, too, looked unfriendly.  6it was as neat as a pin, with a locked bookcase in one corner and a paddle on miss spencer's desk; this was long before corporal punishment was banned.  7the perfectly formed alphabet letters on the blackboard also suggested order and discipline.  8as threatening as my teacher and her classroom were, nothing was worse than the end of the school day.  9we students would line up (neatly, of course) to go to our buses.  10then, on our way out, we had to extend our palms, and miss spencer would pop us with a ruler according to how bad we had been that day.  11it's a wonder any of us ever came back the next day!