1. He is the student of our school.
2. He is the student of his school.
[Are both grammatical? Are both mean that there is only one student at school?]
3. They are the students of their school.
4. They are students of their school.
[Can we use both sentences? Does 'the students' mean 'all the students' in #3? Does 'students' in #4 mean some of the students?]
1. Yes, both sentences are grammatically correct. However, they have slightly different meanings.
- "He is the student of our school" suggests that there is a single student who belongs to or represents the speaker's school. It implies that there might be other students from different schools, but this person is specifically associated with "our" school.
- "He is the student of his school" implies that there is a single student who belongs to or represents his own school. In this case, "his" school could refer to any school that the person being described attends, and it may or may not be the same as "our" school mentioned in the first sentence.
Regarding the number of students:
Both sentences, 1 and 2, do not specify whether there is only one student at the school. They simply describe a student who is affiliated with a certain school. It is possible that there are multiple students at the school.
Moving on to sentences 3 and 4:
3. "They are the students of their school."
4. "They are students of their school."
Both sentences 3 and 4 are grammatically correct, but they have slightly different meanings.
- Sentence 3, "They are the students of their school," implies that all the individuals being referred to are students of the same school. The phrase "the students" suggests a collective identity within the context of that particular school.
- Sentence 4, "They are students of their school," does not necessarily imply that all the individuals mentioned are students of the same school. It simply indicates that each individual is a student of his or her own respective school.
So, to summarize, "the students" in sentence 3 refers to all the students of a specific school, whereas "students" in sentence 4 could refer to any group or subset of students, each having their own respective schools.
1 and 2 mean that he is the only student in the school, yes.
3 and 4 can work if you change "of" to "at" or "in." I would also delete "the" from #3.