Here are the answers to the questions based on the pronunciation of the underlined parts:

**I. Choose the word whose underlined part is pronounced differently:**

1. **A.** cygne (pronounced "sine" - different from the others)
2. **B.** homework (the "o" in homework sounds different compared to hope and one)
3. **A.** brother (the "o" in brother sounds different compared to the other options)
4. **A.** cities (the "c" sounds different from the other "ch" sounds)
5. **A.** grandparents (the "e" is pronounced differently than the "e" in uncles)
6. **A.** write (the "w" is pronounced, unlike "well" which has the "w" sound)
7. **B.** hopes (the long "o" sound is different than the others)
8. **A.** cats (the short "a" sound differs compared to other items)
9. **A.** bags (the "a" sound is different than the "o" in schools)
10. **B.** busy (the "u" is pronounced differently than the "u" in summer)

**II. Odd one out:**

1. **A.** mountain (the only geographical feature as the others are rooms)
2. **C.** curly (the only one describing hair type; the others are more general)
3. **A.** ear (the only body part; the others are facial features)

Feel free to ask if you need any explanations or further assistance!