Moon Shadow thought it would be prudent to follow his father's lead in matters of courtesy in
Miss Whitlaw's house.
impolite
thoughtless
sensible
tolerable

2. list two reasons why fossil fuels should no longer be used as a source of energy in america.

the answer is "began" because it is a action that can be done

o'henry used irony in "the gift of the magi". this tool was essential to developing the story's theme by showing that the couple bought gifts for each other that they could not actually use at the moment. in addition, the author used this fact to show that people of the society should treasure the things they've received from others, because you may never know if they sacrificed their most treasured possession to aquire the gift.

the verbal in this sentence is an infinitive. when you want to know the reason of an action, you simply ask the question "why? ". once you know the reason you can answer with "because".

many times we don´t use the word "because" but we can use another expression and that is an "infinitive of purpose". example:

-why did your brother bring a book?

-he brought a book to study.

in the answer above you can see an example of an infinitive sentence, just like in the example of your text. "he couldn´t run fast enough to beat his older sister". so, the answer is infinitive.