How we cite our quotes: (Part.Chapter.Paragraph) or (Part.Paragraph)
Quote #1
Briony knew that if she had traveled two hundred miles to a strange house, bright questions and jokey asides, and being told in a hundred different ways that she was free to choose, would have oppressed her. It was not generally realized that what children mostly wanted was to be left alone. (1.1.13)
Briony is talking about her cousins, who have just arrived. They probably do want to be left alone to some degree, but at the same time they've also just left home because their parents are divorcing. So in that sense they probably wish that they hadn't been left so alone.
Quote #2
She had returned from Cambridge with a vague notion that her family was owed an uninterrupted stretch of her company. But her father remained in town, and her mother, when she wasn't nurturing her migraines, seemed distant, even unfriendly. (1.2.6)
Cecilia is being a teenager. She doesn't know what to do with herself, she can't get along with her parents, she's sneaking cigarettes every chance she gets. It would all be sort of funny if her family didn't ruin her life a couple hundred pages down the road…
Quote #3
He paused to gather his courage. "It's a divorce!"
Pierrot and Lola froze. The word had never been used in front of the children, and never uttered by them. The soft consonants suggested an unthinkable obscenity, the sibilant ending whispered the family's shame. Jackson himself looked distraught as the word left him, but no wishing could bring it back now, and for all he could tell, saying it out loud was as great a crime as the act itself, whatever that was. (1.5.8)
Divorce would have been much less common in the 1930s, when this book is set. It's seen as an embarrassment, and as a result nobody has apparently explained it to the kids—not even (we learn a few sentences later) to fifteen-year-old Lola.