How we cite our quotes: (Chapter.Paragraph)
Quote #4
"But the principal has explained that in America everyone is assigned according to age. Ten years old means fifth grade. And we must observe the American rules, mustn't we?" (3.11)
Americans have the custom of putting kids in grades depending on their age. Shirley has only finished three grades in China, but she's in a new place so she's got to adapt whether or not she likes it, and live by other people's rules.
Quote #5
Suddenly the principal shut one eye, the right one, then opened it again.
Was this another foreign custom, like shaking hands? It must be proper if a principal does it, Shirley thought. She ought to return the gesture, but she didn't know how. So she shut and opened both eyes. Twice. (3.17-18)
It's hard to figure out other people's body language. Shirley can't figure out what a wink from the principal means (the principal probably just meant it as encouragement). She wants to adhere to the customs of her new home, so she blinks back. This misunderstanding is well-intentioned, but the gesture is technically used incorrectly. Shirley will figure it out, though, as she lives and learns.
Quote #6
"Hi, Shirley!" the class shouted.
Shirley bowed deeply. Then, taking a guess, she replied, "Hi!" (3.24)
It's custom versus custom. The American kids at P.S. 8 greet Shirley with a typical "hi," their usual way of welcoming someone. Shirley does the same, but also adds in her own culture's traditional greeting—a bow. She's trying from the beginning to integrate herself into her new home's cultural practices.