My classmate
Huang Jie is one of my classmates. She is twelve years old. She has long hair, big eyes and small nose. My classmate likes reading book, playing computer games, listening to music, but sometimes she likes playing sports. I like her.
x
﹣3
﹣2
﹣1
0
1
2
3
4
5
y
12
﹣4
给出了结论：
⑴二次函数y=ax2+bx+c有最小值，最小值为﹣3；
⑵当 −12<x<2 时，y＜0；
⑶二次函数y=ax2+bx+c的图象与x轴有两个交点，且它们分别在y轴两侧．则其中正确结论的个数是（ ）
在①油脂 ②淀粉 ③蛋白质 ④纤维素四种物质中，能发生皂化反应的是 ____（填序号，下同），遇碘显蓝色的是 ____，可用于造纸的是 ____
