下列各式中，不是整式的是（ ）
A：6xy
B：yx
C：x+9
D：4
A. I'd like some carrots and fish.
B. I'd like some juice and chicken.
C. I'd like some rice and vegetables.
D. I'd like some beef and bread.
如图是制作洋葱鳞片叶表皮细胞临时装片的实验步骤，请据图回答：
计算：（π﹣1）0+ (12)-1+|5-27|﹣23．
