1. AROUND - adverb (It relates to the word looked in the sentence. The word around tells how he and his friends looked.)
2. BEFORE - adverb (The word before is an adverb when it is not followed by a noun, and preposition if it is followed by a noun. In this case, it is an adverb.)
3. into
4. at
5. in
6. on, around
7. for, of
It means that to insure safety upon students and faculty in the building, you must sign in with the front desk which is usually in the main office, drugs are not tolerated and weapons are not allowed. No one that either has an appointment or is a student or faculty member may enter the meeting or it would be seen as trespassing..
I would say space or a formula in math. Look up the definition in a dictionary!
