which sentence includes a dependent clause?

1. They gave sandwiches to the children on paper plates.
2. When looking out the window, they saw the first leave fall.
3. On the way to the store, Nicole saw a lost cat.
4. The boy received a dog named rover for his birthday.

2. When looking out the window, they saw the first leave fall.

The sentence that includes a dependent clause is:

2. When looking out the window, they saw the first leaf fall.

The sentence that includes a dependent clause is:

2. When looking out the window, they saw the first leaf fall.

To identify a dependent clause within a sentence, we need to look for a group of words that contains a subject and a verb but cannot stand alone as a complete sentence. In this case, the dependent clause is "When looking out the window," because it does not express a complete thought on its own.