Determine the category of "friendly" in the following sentence. Use the substitution and co-ordination tests to justify your answer:

David gave Mary friendly advice.

Despite the -ly ending, friendly is an adjective in this case. It modifies the noun "advice".

(Most modifiers ending with -ly are adverbs; this is an exception)

How do you perform the co-ordination test, I'm at a loss

To determine the category of the word "friendly" in the sentence "David gave Mary friendly advice," we can use the substitution and coordination tests.

First, let's apply the substitution test. We can try replacing the word "friendly" with a word from each major syntactic category (noun, verb, adjective, adverb) and see which one works best in the sentence.

1. Noun: David gave Mary cat advice. - This does not make sense semantically.
2. Verb: David gave Mary read advice. - Again, this doesn't make sense.
3. Adverb: David gave Mary quickly advice. - This doesn't seem appropriate either.

Finally, let's try using an adjective, as "friendly" seems to be modifying the noun "advice":
David gave Mary helpful advice. - This sentence still makes sense and has a similar meaning to the original sentence.

Based on the substitution test, "friendly" appears to be an adjective.

Next, let's apply the coordination test. This test involves coordinating two phrases with the word "and" to see if they can be combined smoothly.

David gave Mary friendly advice and encouragement. - This coordinate structure sounds natural and coherent.

Based on the coordination test, "friendly" can be coordinated with other adjectives.

Therefore, "friendly" is determined to be an adjective in the sentence "David gave Mary friendly advice" based on the substitution and coordination tests.