The first box is a dangling modifier. The second is a clause. The last is a phrase. (Answers going from top to bottom) :)
It indicates that Huck frequents places perhaps grocery stores where the conditions are not sanitary what with "sickly eggs and rotten cabbages and dead cats" in other words, Huck cannot afford to frequent fancier shops or fancier homes because he is poverty stricken and used to such sights.
I want to go, but I have to feed my spider.
Do you have sentence choices? I could help.
