Yes. All programmed texts include immediate answer keys built into the page design.
Most learners confuse I/me or he/him. Krohn uses substitution tables to force memorization of the case system. englishsentencestructurerobertkrohnpdf link
If you are unable to locate the original Krohn PDF, do not despair. Here are modern books that use the exact same structural, pattern-practice approach: Krohn uses substitution tables to force memorization of
| Book Title | Author | Why It’s Similar to Krohn | | :--- | :--- | :--- | | Understanding and Using English Grammar | Betty Azar | Uses a "grammar chart" approach with sentence patterns. | | English Grammar in Use | Raymond Murphy | Self-paced, left-page explanation, right-page exercises. | | The Sentence Structure Workbook | Geraldine Woods | Focuses entirely on clauses, phrases, and sentence cores. | | | English Grammar in Use | Raymond