The event at 11N. Elm was significant for Montag. Here he meets Mrts. Blake, the owner of the house filled with books that they have to burn. She is adamant not to leave her house and books. Before she gets burned with her books, the woman said the quote "Play the man, Master Ridley; we shall this day light such a candle, by God's grace, in England, as I trust shall never be put out." This line is very significant because the woman wants to imply that may her death serve as the spark that will light up a revolution against the government and their stamping out of free thinking. She wants to serve as an example on why she is willing to sacrifice her life for her beliefs. It is significant in understanding fahrenheit 451 because it is the turning point for the protagonist Montag to finally go with his principles and go against the government.
"Swinging in the air" is a dangling modifier in this sentence since it modifies the part of the sentence "by the acrobats" but it is ambiguous or not clear because it may also modify "the children". A dangling modifier is a grammatical contruction that can be misinterpreted because of the way it was written and it can also lead to misunderstanding of a sentence or idea.