Each of the following complex sentences has one independent and one dependent clause. Identify the dependent clause, and write whether it's used as an adjective or as an adverb.
25. Read the opinions of the best authorities on the subject before you make up your mind.
26. Martin Van Buren, who was the eighth president of the United States, was a native of New York state.
27. Please close the book that is on your desk.
28. The paint that you ordered for the kitchen wall is washable.