we sat telling the stories in the dark. 為什麼sat的後面不加逗點 這不是分詞構句嗎?

Verbal phrases that are not essential to the meaning of the sentence are separated by commas, otherwise no comma is needed.

verbal (or called non-finite verb) includes (1) infinitive, (2) participle and (3) gerund.

Some intransitive verbs can take infinitive phrase and/or participle phrase as their adjunct (修飾).
Transitive verbs take gerund phrase as their direct object.

We sat telling the stories in the dark.

"telling the stories in the dark" is a participle phrase, which is essential to the meaning of the sentence, so no comma is needed.

This participle phrase functions as adverb to modify the intransitive verb "sat".

Other example:
I like telling stories in the dark.

"like" is a transitive verb and "telling stories in the dark" is a gerund phrase, acting as direct object of the verb "like".

We sat telling the stories in the dark. 為什麼sat的後面不加逗點 這不是分詞構句嗎?

We sat telling the stories in the dark.
????我們在黑暗中坐著説故事。

☆ 因為這個是完整的句子, “ telling the stories in the dark”是“noun clause ”名詞片語, 用作修飾前一動詞“ sat "。

☆ 我們坐下了, 幹啥呢？所以不必放“ , ”囉。

例：Such as Paris and New York, in that its *shopping areas are so 
widely.*
例如巴黎和紐约, 在那裡它的購物地區是如此的廣濶。

謹供参考, 謝謝！????

sat是什麼？費解！？