Background for Teachers
There are several things that we need to keep in mind here:
1. KISS may be the only pedagogical grammar that even attempts to teach students how to analyze the structure of their own sentences.Students unintentionally suggested the need for this exercise as they analyzed randomly selected sentences. For example, in the sentence "This castle is enchanted," some students will label "enchanted" as a predicate adjective. As the instructional material suggests, this is a valid explanation. It is, after all, an "enchanted castle." But these same students will tend to eliminate traditional passive voice by labeling all such sentences in the same way.
A primary purpose of this exercise is to stop the students from doing the latter, while simultaneously recognizing the students' intelligence. Passive voice is an important stylistic and semantic concept. But to understand passive voice, students need to recognize that the verbs in question are part of the verb phrase. I'd suggest, therefore, that you use this exercise to explain that there are times when a verb (technically a "verbal") can function as a predicate adjective, but at the same time encourage them, for now at least, to consider these verbs as part of the verb phrase.
Put differently, seeing these verbs as predicate adjectives is a fine point, but it is a fine point that many students will see for themselves. Because they will do so, we need to address the question. Most textbooks, however, do not consider these verbs as predicate adjectives. They consider all of the sentences in these exercises as passive voice. (In KISS statistical studies, they are all counted as passive voice.) Let's give students credit for their intelligence and address the question.