Here are the answers for the "Find the word which has a different sound in the underlined part" exercise:

1. B. appear (The "ea" in appear sounds like "ee" while the others have the "e" sound)
2. D. fair (The "ai" in fair sounds like "ay" while the others have the short "e" sound)
3. C. here (The "e" in here sounds like "i" while the others have the short "e" sound)
4. B. stair (The "ai" in stair sounds like "ay" while the others have a single vowel sound)
5. D. prepare (The "ea" in prepare sounds like "ee" while the others have a single vowel sound)
6. C. many (The "a" in many has a long "a" sound while the others have a short "a" sound)
7. C. engineer (The "eer" in engineer has a different sound compared to the single vowel sounds in the others)
8. B. towel (The "ow" in towel creates a different sound compared to the single vowel sounds in the others)
9. A. mine (The "i" in mine has a long "i" sound while the others have short vowel sounds)
10. B. should (The "ou" in should has a different sound compared to the single vowel sounds in the others)
11. C. milk (The "i" in milk has a long "i" sound while the others have short vowel sounds)
12. B. pizza (The "i" in pizza has a short "i" sound while the others have long vowel sounds)
13. A. impressed (The "e" in impressed has a short "e" sound while the others have long vowel sounds)
14. D. opened (The "ed" in opened creates a different sound compared to the single vowel sounds in the others)
15. B. routine (The "ou" in routine creates a different sound compared to the short "i" sound in finished)