Let's analyze the given passage and focus on filling in blank No. 3. The sentence containing blank No. 3 is: "...and had totally lost (3) __________ in a book...".

The sentence describes Gabriella Montez (referred to as 'she') being deeply absorbed in a book. The phrase "lost ______ in something" is a common idiom used to describe becoming completely engrossed or absorbed in an activity, thought, or object. When the subject of the verb "lost" is also the one being lost (i.e., absorbed), we use a reflexive pronoun.

The subject of the verb "had lost" is "she". A reflexive pronoun refers back to the subject of the clause. For the subject "she", the corresponding reflexive pronoun is "herself".

Let's look at the provided options for blank No. 3:

• itself: This reflexive pronoun is used for inanimate objects or animals (when the subject is 'it'). The subject here is a person ('she'), so 'itself' is incorrect.
• himself: This reflexive pronoun is used for a male subject ('he'). The subject here is female ('she'), so 'himself' is incorrect.
• ourself: This is not a standard English reflexive pronoun. The plural reflexive pronoun for 'we' is 'ourselves'. Also, the subject is singular 'she', not 'we', so this option is incorrect.
• herself: This reflexive pronoun is used for a female subject ('she'). This matches the subject of the sentence, Gabriella Montez ('she'). The phrase "lost herself in a book" means she became completely absorbed or engrossed in the book, which fits the context of her being comfortably curled up and enjoying the peace and quiet.

Therefore, the most appropriate word to fill in blank No. 3 is "herself". The complete phrase is "had totally lost herself in a book".

Let's read the sentence with the chosen word:

"...and had totally lost herself in a book which was the best she had (4) _________ read..."

This sentence makes perfect sense in the context of someone being deeply engrossed in reading.

Revision Table: Understanding Pronouns in Passage Completion

Additional Information: The Idiom "Lost Oneself In"

The phrase "to lose oneself in something" is an idiomatic expression. It means to become completely absorbed in an activity, thought, or feeling to the point where one is unaware of their surroundings or the passage of time. In the context of reading, "losing oneself in a book" means becoming so engrossed in the story or content that everything else is forgotten.

• It implies deep concentration and enjoyment.
• It is often used with activities like reading, music, work, a hobby, or even thoughts.
• The structure is typically "Subject + lose + reflexive pronoun + in + [activity/object]". For example:
  • He lost himself in his work.
  • They lost themselves in the music.
  • We lost ourselves in conversation.

Understanding such idiomatic expressions is crucial for accurately filling blanks in passage completion questions, especially when they involve pronouns or prepositions that are part of the idiom.