题目

Alone in the wilderness. Nothing but jungle. A world of shadow with the rays of light falling like blonde hair from the crowns of the giant trees. Jungle in the midday sun. Everything motionless. Not a sound from sky or earth. Complete silence. Only some coconuts falling, at long intervals, very far away. The world reduced to the soft touch of cool grass along my naked back, and a sweet smell of rich soil and vegetation. Stretched out with closed eyes beside my heavy burden of fruit and firewood, I enjoyed the feeling of fresh blood streaming through every part of my body and fresh jungle air 12．一个三角形的三个外角之比为5：4：3，则这个三角形内角中最大的角是90度．