Without direct access to Robert Krohn's 2021 PDF on English sentence structure, I can suggest that his work likely covers these foundational aspects and may offer additional insights into:
Using "who," "which," or "that" to combine ideas.
: Adjectives and adverbs modify nouns and verbs, respectively, providing more detail about the words they modify.
: Combine basic clauses using coordination and subordination to express sophisticated thoughts. 💻 Accessing the Book in the Digital Era