Based on the analysis of the pronunciation of the given words, here are the answers for each question:
1. **D. open** - The underlined part "o" is pronounced differently as /oʊ/ compared to the other words, which have a more central vowel sound.
2. **C. one** - The "o" in "one" is pronounced as /wən/, which is different from the other words that have a clear /oʊ/ sound.
3. **A. brother** - The "o" in "brother" is pronounced as /ʌ/ (as in /ˈbrəðər/), while the other words have a different vowel sound.
4. **A. cities** - The "i" in "cities" is pronounced as /ɪ/, while the other words contain different vowel sounds.
5. **C. uncles** - The "u" in "uncles" is pronounced as /ʌ/, whereas the other words have different vowel sounds.
6. **A. books** - The "oo" in "books" is pronounced as /ʊ/, which is different from the other words.
7. **C. takes** - The "a" in "takes" is pronounced as /eɪ/, while the others have different vowel sounds.
8. **C. these** - The "ee" in "these" is pronounced as /i/, which differs from the others.
9. **B. river** - The "i" in "river" is pronounced as /ɪ/, while the others have different sounds.
10. **B. mine** - The "i" in "mine" is pronounced as /aɪ/, while the others differ.
11. **D. tea** - The "ea" in "tea" is pronounced as /i/, different from the others.
12. **C. great** - The "ea" in "great" is pronounced as /eɪ/, which is different from the others.
13. **A. leave** - The "ea" in "leave" is pronounced as /iː/, which is different from the others.
14. **C. Sunday** - The "u" in "Sunday" is pronounced as /ʌ/, while the others have different vowel sounds.
15. **A. but** - The "u" in "but" is pronounced as /ʌ/, which is different from the other words.
Summary of words with different sounds:
1. D. open
2. C. one
3. A. brother
4. A. cities
5. C. uncles
6. A. books
7. C. takes
8. C. these
9. B. river
10. B. mine
11. D. tea
12. C. great
13. A. leave
14. C. Sunday
15. A. but
1. B. library (The other options are all rooms in a house, while a library is a separate building or a section of a building for books.)
2. B. dishwasher and A. sofa (However, if I must choose only one, I'll say B. dishwasher and A. sofa doesn't belong because the other options are things found in a kitchen, while a sofa is found in a living room. Dishwasher also can be found in a laundry room. Or the other way round B. dishwasher belongs to a kitchen, A. sofa is the odd one)
3. A. apartment and B. villa, C. room, D. hotel doesn't belong because an apartment, a villa, and a room are all types of accommodations, while a hotel is a building that provides accommodations.
Or A. apartment and B. villa and C. room belong together, D. hotel doesn't belong because the other three are places you can own.
4. B. flat (The other options are all rooms in a house, while a flat is another word for an apartment, which is a type of dwelling.)
5. B. cook (The other options are all objects or appliances, while "cook" is a verb, referring to the act of preparing food.)
1. A. I like
2. B. to ski
3. C. length
4. B. no
5. A. How beautiful
6. C. with
7. B. a little
8. nicer