Final answer:
The incorrect verb pair is 'teach-thought'; the right past tense of 'teach' is 'taught'. 'Thought' is the past tense of 'think'.
Step-by-step explanation:
Among the examples provided of the base and past tense forms of verbs, the incorrect pair is d. teach-thought. The correct past tense of 'teach' is 'taught', not 'thought'. In reality, the correct past tense for 'teach' is 'taught.' It is imperative to recognize these nuances for precise grammar application in both written compositions and spoken language. Therefore, the pairs should be: a. fly-flew, b. send-sent, c. win-won, and d. teach-taught. 'Thought' is actually the past tense of 'think'. Understanding the correct past tense forms of verbs is important for proper grammar usage in writing and speaking. In reality, the correct past tense for 'teach' is 'taught.' It is imperative to recognize these nuances for precise grammar application in both written compositions and spoken language.