The causes of bush fires are threefold: natural (caused by lightning or the sun's rays), accidental (usually by human error or carelessness) or deliberate (caused willfully).
The causes of bush fires are threefold: natural (caused by lightning or the sun's rays), accidental (usually by human error or carelessness) or deliberate (caused willfully).
造成山火的原因有3﹕自然现象（由闪电或阳光造成）、意外产生（多数由人为错误或疏忽所引致），或是蓄意破坏。