Explain the concept of a complex sentence and provide examples.

A complex sentence is a type of sentence that consists of an independent clause and at least one dependent clause. An independent clause is a complete sentence that can stand alone, expressing a complete thought, while a dependent clause is a sentence fragment that cannot stand alone and relies on the independent clause for its meaning.

The dependent clause in a complex sentence usually functions as an adverbial, adjectival, or nominal clause, providing additional information or modifying the independent clause. It adds complexity and depth to the sentence by expanding on the main idea or providing more details.

Here are some examples of complex sentences:

1. Although it was raining, they decided to go for a walk.
- In this example, "Although it was raining" is the dependent clause, and "they decided to go for a walk" is the independent clause. The dependent clause provides additional information about the circumstances, explaining why they still decided to go for a walk despite the rain.

2. I will go to the party if I finish my work on time.
- In this example, "if I finish my work on time" is the dependent clause, and "I will go to the party" is the independent clause. The dependent clause acts as a condition, stating that the speaker will only go to the party if they finish their work on time.

3. The book that I borrowed from the library was very interesting.
- In this example, "that I borrowed from the library" is the dependent clause, and "The book was very interesting" is the independent clause. The dependent clause functions as an adjectival clause, providing additional information about the book by specifying where it was borrowed from.

4. She couldn't attend the meeting because she was feeling unwell.
- In this example, "because she was feeling unwell" is the dependent clause, and "She couldn't attend the meeting" is the independent clause. The dependent clause explains the reason why she couldn't attend the meeting.

Complex sentences allow writers to convey more complex ideas and relationships between different parts of a sentence. By combining independent and dependent clauses, they provide a more nuanced and detailed understanding of the information being communicated.