The boys had put out the campfire,The fire wasn't ().A.on fire B .alight ,为什么填B ,俩个意思那么相近,

问题描述:

The boys had put out the campfire,The fire wasn't ().A.on fire B .alight ,为什么填B ,
俩个意思那么相近,

on fire 是adv(副词)用法.
alight 是 adj(形容词)用法.
原因就像是Baby is asleep/awake.一样
这算是语法,没听说过is后加单个副词(有时会用副词修饰形容词)