We are given the following statements and conclusions:
1. Statement I: "At most teachers are boys" means that the number of teachers who are boys is less than or equal to the total number of teachers. However, this doesn't directly imply that some teachers must also be students.
2. Statement II: "Some boys are students" tells us that there are students who are boys, but this doesn't mean that some teachers are students.
Now, let's evaluate the conclusions:
- Conclusion I: "Some teachers are students." This follows logically because it is possible that some teachers are also students. Given that some boys are students, it's plausible that some teachers, who might be boys, could also be students.
- Conclusion II: "Some students are boys." This conclusion follows directly from Statement II, so it is valid.
Thus, only conclusion I follows, and the correct answer is \( \boxed{\text{Only I follows}} \).