I suppose so.
I'm not really sure.
don't agree mostly
Yes,but... - That one confuses me. That's because it means nothing
I agree in theory, but.. Not useful, means nothing
That's absolute rubbish - is it rude way of disagreeing ? Yes
Note that in forms, etc. there's usually a symmetry in the way things are phrase, so that when they reduced the answers to numbers (1 - 9), there is some consistency is difference between the choices.
Why we don't use "had better" on signs in public places ? Is it becouse that sounds like a threat ?
You mean like "You'd better STOP"
"You'd better Not Turn Right at the next intersection or, by God, I'll ..."
I've got a better idea. Why don't you tell us why we should use "had better" on signs?
3. Sorry, don't understand this one.