Question

leave at once ( I don't know how to punctuate this sentence I thought I would use a period but it could be a exclam mark!)

Answer 1

@KyanTheDoodle

Answer 2

Going by the most connventional expression of the English language I would use exclamation mark. "Leave at once" itself involves anger otherwise it wouldn't be used.

Answer 3

Yeah. An exclamation mark would be a good choice. Maybe if you want to make it longer you can put it as "You better leave at once!"

Answer 4

However if you put please then you would use period:)

Answer 5

What do you say Kyan ?

Answer 6

Indeed

Answer 7

Leave at once if you may.

Answer 8

Leave at once if you please.

Answer 9

I think thisquestion is too ambiguous to begin with

Answer 10

thanks @KyanTheDoodle and @Robert136