Not Only...But Also Error Correction

This Not only...but also error correction exercise targets the mistakes learners make most often with emphatic inversion: forgetting the auxiliary after fronted Not only, choosing the wrong auxiliary for the tense, and inverting the but also clause when it should stay in normal word order.

Wrong: "Not only the course was practical, but also was it affordable." Correct: "Not only was the course practical, but it was also affordable."
Wrong: "Not only did the manager explained the delay, but also did she apologise." Correct: "Not only did the manager explain the delay, but she also apologised."

Because this page asks you to edit only the wrong chunk inside full sentences, it trains the proofreading decision that transformation practice cannot fully test. Some sentences are already correct, so you must decide whether the question-like first clause is valid inversion, whether do/does/did has forced a base verb, and whether the second clause after but should be left alone.