你可以通过画三角形来做，我用圆圈来标记，从分布图的起始点到终点。

You can do it by drag triangles, which I have marked with circles, to the start and end points of the histogram.

youdao

黄色标记的起始点(A)，和蓝色标记的结束点(B)。

The yellow marker is the start point (a), and the blue marker is the end point (b).

youdao

黄色标记的起始点(A)，和蓝色标记的结束点(B)。

The yellow marker is the start point (a), and the blue marker is the end point (b).

youdao