The firemen saw the fire.The firemen began to fight against the fire.(合并一句）
问题描述：
The firemen saw the fire.The firemen began to fight against the fire.(合并一句）
--------- ---------- the fire,the firemen began to against the fire.
答
On seeing the fire,the firemen began to against the fire.一看见,就开始灭 那就给你解释下吧：on作为介词有这种用法表示：在...的时候,在...后立即比如：He jumped with joy on hearing the news.他一听到这个消...