题干
想一想，结合本课所学的知识，写一份家庭安全防火须知
Fire safety at home
We must not……
We must ……
When there is a fire, we……
答案(点此获取答案解析）
We must not play with a fire at home
We must be careful with fires.
When there is a fire, we must go outside quickly and never take the lift. We must call 119.
We must be careful with fires.
When there is a fire, we must go outside quickly and never take the lift. We must call 119.
SO2能表示的意义是：