题目

A father and his son went to a kite-flying festival. The son was happy when he saw the sky filled with colorful kites. He wanted to fly a kite, too 【1】The son started to fly the kite. 【2】.After a while，the son said, “Father，it seems that the string(线）is stopping the kite from flying higher. If we cut it, it will be free and fly even higher. Can we cut it?” The father cut the string off of the reel (线轴).【3】.This made the little boy happy.【4】 It soon fell to the ground. The son was surprised to see this. He asked his father, “I thought that after cutting the str用边长相等的黑色正三角形与白色正六边形镶嵌图案，按图①②③所示的规律依次下去，则第n个图案中，所包含的黑色正三角形和白色正六边形的个数总和是（ 　　）。A．+4n+2B．6n+1C．+3n+3D．2n+4