what does "booked into evidence" mean as in:
"A gun was booked into evidence."
most dictionaries show that "evidence" doesn't mean an evidence room.
It was recorded as belonging to the group of items that collectively form the evidence related to a crime.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.