A three paragraph essay will have only one strong point in its thesis; in other words, there should be a topic sentence written as the last sentence of the introductory paragraph. This introductory paragraph should begin with an observation relevant to the topic before moving into the thesis statement. The next paragraphs develop the thesis with statements that have supporting details from the text, along with examples, and explanations.
In other words, the body paragraphs develop and support the thesis; also, in the last paragraph there should be a concluding sentence that is a summation of the thesis and main points of the essay.
Regarding the questions on pity:
Here is an earlier passage in the play as Annie Sullivan speaks with Mr. Anagnos at the Perkins Institute before she leaves for Alabama and the Kellers' home:
ANAGNOS: Annie, be humble....You will need their affection, working with this child.
ANNIE: I hope I won't need their pity.
ANAGNOS: Oh, we can all use some pity.
Perhaps, then, the pity that is given to a person should be only enough that causes the giver to become patient in his or her behavior management and teaching. When Annie declares that she wants no pity, she means that she does not want people to feel sorry for her. But, when Mr. Anagnos says that all people can use some pity, he implies that they need compassion. For, by exercising compassion, a person will have patience with others; therefore, if Annie has this understanding and compassion for Helen, she will be a more effective teacher of this girl.
In the narrative of Gibson's play, Annie never pities Helen for being blind and deaf; instead, she demands that Helen behave. On the other hand, she does pity Helen's condition that causes the girl such frustration; so, Annie is stalwart and patient as she continues to spell out words for Annie in the girl's hand. And, she perseveres in her compassion for Helen. Eventually, Annie breaks through the barriers of Helen's handicaps and reaches Helen's brain, as it finally makes the connection between things and their names.