Simile: "Long ropes strung cross the playground were covered with still more da-zi-bao, looking like laundry hung out to dry." I think this means that the students wrote and hung too much "da-zi-bao's" that it looks like a massive amount of laundry in the sun, prepared to be dried.
Personification: "The characters danced before my eyes, growing larger and redder, almost swallowing me up." I think this shows the shock Ji-li felt at time. I think this shows how dizzy and confused she felt that that outrageous statement.
Rhetorical Question: "Did the teachers really intend to ruin our health and corrupt our minds?" I think thus question shows how Ji-li is confused with the current situation in the book, where the students are criticizing the teachers for everything. Personally, I do not think that the fault in the students' skills are not the teacher's fault, but apparently, the others do not think so.
Foreshadowing: "“Alone in the corner of the school yard I saw a little wildflower. She had six delicate petals, each as big as the nail of my little finger. They were white at the center and shaded blue at the edges. She was as lonely as I was. I did not know her name. Softly I stroked her petals, thinking that I would take care of her, as I wished someone would take care of me." I think this tells me how something will happen to Ji-li in the future. Something that will cure her from her "depression."