Is this a sentence fragment? Using instruments called geophones, scientists measuring seismic waves caused by traffic to learn how urban life affects the earth.

type of error:

the error in the sentence is a "dangling modifier". a dangling modifier is a phrase, word or clause that "dangles" because there is not target to modify. in this case, "after mopping the floor" is the dangling modifier since it has no word to modify. the noun "house" cannot mop the floor; therefore there is a mistake in the writing of the sentence.

and your question what topic are you in trouble with?

in the story "marionettes inc," in the last line of the story, braling two is referred to by the narrator as the "someone." what does this new identifier imply and how does it add to the drama of the closing scene?

because most jews were in the concentration camps and dying horrible deaths while anne could be with her family in a warm place with shelter, food, water, and a place to sleep.