When I visited them last night ,they __ (chat) by the fire.

问题描述:

When I visited them last night ,they __ (chat) by the fire.

When I visited them last night ,they chatting by the fire.当我昨天拜访他们的时候,他们正在围着火炉交谈!某一个时点上,某件事情处于正在进行的状态!