hot－带电的，充电的 hot wire－高压电线

fireman－消防队员

cause－引起，原因

cigarette end－烟头

remains－尸体，残骸

electric wire－高压线

power line－电力线

solve the mystery－解迷

snatch－抓住

spark－电火花

The fireman finally found out the cause of forest fire. They discovered that: there was a remains of snake wounding round electric wire. A bird snatched a snake from ground and then dopped it on power line, so that hot snake had got spark down ground to cause the fire.