1. He is taking a walk at the park.

2. He is taking a walk in the park.
3. He is taking a walk on the park.
4. he is taking a walk near/ in front of the park.
[Does #1 mean #4? Or does #1 mean #2 or #3?]

5. He is reading a book at the library.
6. He is reading a book in the library.
7. He is reading a book near the library.
[Does #5 mean #7? Or does #5 mean #6?

#1 means the same as #2. #3 is not used!!

#4 is OK with either variation, but does not mean the same as #1.

#5 means the same as #6, not #7.

In the context of these sentences, let's discuss the differences:

1. "He is taking a walk at the park."
2. "He is taking a walk in the park."
3. "He is taking a walk on the park."
4. "He is taking a walk near/in front of the park."

Regarding the meaning of sentence #1, it does not necessarily mean the same as sentence #4. Sentence #1 suggests that the person is currently at the park and is taking a walk. It does not specifically indicate if they are inside the park or near it. On the other hand, sentence #4 focuses more on the person being in the vicinity of the park, either nearby or directly in front of it.

In sentence #2, "He is taking a walk in the park," it implies that the person is inside the park while walking. It suggests that the person is physically present within the boundaries of the park.

Sentence #3, "He is taking a walk on the park," does not sound grammatically correct. However, if we consider "on" as a typo or mistake, and assume it should be "in" instead, then it would have the same meaning as sentence #2.

Regarding the next set of sentences:

5. "He is reading a book at the library."
6. "He is reading a book in the library."
7. "He is reading a book near the library."

Sentence #5, "He is reading a book at the library," indicates that the person is currently at the library and is engaged in reading a book. It does not specify if they are inside the library or in the vicinity of it.

In sentence #6, "He is reading a book in the library," it means that the person is inside the library and reading a book. It suggests that they are physically present within the library premises.

Sentence #7, "He is reading a book near the library," implies that the person is close to the library but might not necessarily be inside it. They could be in a location nearby or in the immediate vicinity of the library.

To summarize, in the given context, sentence #1 does not necessarily mean the same as sentence #4, and similarly, sentence #5 does not necessarily mean the same as sentence #7. The specific meaning depends on whether the person is inside, outside, or in the vicinity of the park or the library.