直线，圆形，正方形，三角形。

Line, circle, square and triangle.

youdao

多少条直线组成一个三角形？

How many make a triangle?

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这些三角形的一边会排成一条共同的直线。

Then one side of each of these triangles is brought into a common alignment.

youdao

这些三角形的一边会排成一条共同的直线。

Then one side of each of these triangles is brought into a common alignment.

youdao