围绕本课标题 Hot snake 触电的蛇（森林大火之谜）主题，AI 老师会出 若干个简单问题，
每个问题听完后，用 完整句子口头作答。
⚠️ 尽量说完整句子，不要只说一个词；优先用本课句型与词语：put out a big forest fire / have been trying to find out how the fire began / caused by broken glass or by cigarette ends / examined the ground carefully / a fireman accidentally discovered the cause / the remains of a snake / wound round the electric wires / a 16,000-volt power line / solve the mystery / A bird had snatched up the snake / sent sparks down to the ground / started a fire