人要对自己的行为负责，原因是（    ）

看图，读一读，将字母序号写在横线上。

A. I like this plant. It's short. It has small leaves. It has three red flowers.

B. This is my plant. It's small. It has two small leaves. I water it every day.

C. There are two seeds. They are under the ground. They drink the rain water.

D. I have a new plant. It's green. It has long leaves. It has small flowers too.

如图，在y轴正半轴上依次截取OA₁=A₁A₂=A₂A₃=…=A_n﹣1A_n（n为正整数），过点A₁，A₂，A₃，…，A_n分别作y轴的垂线，与反比例函数y=$\frac{2}{x}$（x＞0）交于P₁，P₂，P₃，…，P_n，连接P₁P₂，P₂P₃，P₃P₄，…，P_n﹣1P_n，得梯形A₁A₂P₂P₁，A₂A₃P₃P₂，A₃A₄P₄P₃，…，A_nA_n+1P_n+1P_n，设其面积分别为S₁，S₂，S₃，…，S_n，则S_n=（　　）

小明想做一个直角三角形的木架，以下四组木棒中，哪一组的三条能够刚好做成（　　）