What he said is a subordinate clause.

What is the main clause of this sentence?

I feel that my lymph nodes are swollen.

Qingming Festival is a day to clean the ancestors' graves and show respect.

This text is organized using section signs.

Jörmungandr is a gigantic sea serpent in Norse mythology.

He was working until late at night.

He is clearly a night owl, working late into the night and sleeping late into the morning.

We have our wedding on the twenty-fourth.

Our project is scheduled to be completed on the fourteenth.