I saw two birds land on the roof of our porch period one bird had a twig and it's beak. the other bird had a piece of string. which sentence could kobe added to the passage to best vary the kosentence pattern and affect the fluency?

⭕I think they were a male and female robin.

⭕ then they flew to the corner of the porch.

⭕ I sat quietly and watches they began to build a nest.

⭕ without a care, the little Carpenters got to work on a nest.