Which sentence includes a dependent clause?

1. The package was heavy
2. She smiled as she opened the package
3. It was a fancy hat!
4. Today is her 16th birthday

2. She smiled as she opened the package

The sentence "She smiled as she opened the package" includes a dependent clause.

To identify the sentence that includes a dependent clause, we need to understand what a dependent clause is. A dependent clause is a group of words that contains a subject and a verb but cannot stand alone as a complete sentence because it does not express a complete thought.

Now let's analyze each sentence to find the dependent clause:

1. "The package was heavy" - This sentence does not include a dependent clause because it expresses a complete thought and can stand alone as a sentence.

2. "She smiled as she opened the package" - This sentence includes a dependent clause: "as she opened the package." This clause "as she opened the package" is dependent because it doesn't express a complete thought on its own.

3. "It was a fancy hat!" - This sentence does not include a dependent clause because it expresses a complete thought and can stand alone as a sentence.

4. "Today is her 16th birthday" - This sentence does not include a dependent clause because it expresses a complete thought and can stand alone as a sentence.

Therefore, the sentence that includes a dependent clause is sentence number 2: "She smiled as she opened the package."