most of the time, once you work out that an expression is an adjective (for example), you can assume it is an adjective in other situations, unless it clearly is not.
Sometimes it isn't obvious whether a word or expression is an adjective or something else, which is why I came up with the sentence "He has pro-China/Chinese sympathies", where "pro-China" and "pro-Chinese" are clearly adjectives. If they are adjectives in that sentence, it is reasonable to assume they are adjectives in other sentences as well. **