下图左是制作洋葱表皮细胞临时装片的基本步骤。若在显微镜中观察到的图像如下图右所示,则制作装片步骤中最可能有问题的是( )
A:①
B:②
C:③
D:④
The place _____the bridge is supposed to be built should be _____the cross river traffic is
the heaviest.
圈一圈,算一算。
圈一圈____
13-8=____
12-8=____