Final answer:
To combine sentences using relative pronouns, connect details to the subject by creating a relative clause.
Explanation:
To combine the sentences, you can say, 'I lent you a book which was written by one of my friends.'
Here's an example: The book that the children read was interesting.
By using relative pronouns like which, who, whom, you can connect two sentences into one, adding more detail about the subject.
Learn more about relative pronouns and sentence structure here:
https://brainly.com/question/24203375
