I need help on this quickly. PRONOUNS:
I
ME
HE
SHE
IT
HIM
HER
YOU
WE
THEY
THEM

the pronoun reference replaces a noun, but you have to make sure there's no room for confusion.

in the first sentence "her" could be referring to shely or to the sister. the answer there is "shelly called her sister and told her about the new baby."

in the second sentence "it" could be referring to the roof or the floor. the answer there is "since the roof leaks on the family room floor, we need to repair the roof."

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.