1. He doesn't see any students in front of the school.
2. He doesn't see any student in front of the school.
[Are both okay? Which one is common?]
Both are fine. #1 is probably used more often, but it would depend on what question was asked, to which this is the answer.
2. He doesn't see any student in front of the school.
3. He doesn't see a single student in front of the school.
[Does #2 mean #3?]
Both sentences are grammatically correct, but they have slightly different meanings and usage.
1. "He doesn't see any students in front of the school." This sentence implies that the person does not see multiple students in front of the school. It suggests that there may be no students at all, or that there are simply none in the immediate area in front of the school. This sentence is commonly used when referring to the presence or absence of multiple individuals.
2. "He doesn't see any student in front of the school." This sentence implies that the person does not see a single student in front of the school. It suggests that there may be other people present, but specifically, there is no student visible. This sentence is commonly used when referring to the presence or absence of a singular individual.
In common usage, the first sentence ("He doesn't see any students in front of the school") is more common as it allows for a broader interpretation and includes the possibility of multiple students. However, the choice between these two sentences depends on the specific context and what you want to convey.