the law of proximity in grammar

could you please lecture me a little bit on the law of proximity in grammar? pardon me if I get the spelling wrong.

I presume that you are speaking of proximal concord, in which a verb may agree in number with a nearer noun rather than with its grammatical referent.

A group of boys are standing over there. – Although the sentence subject is singular (group), the verb is plural (are) because the concept ‘boys’ (a plural noun) is nearer it.

It is not a ‘law’ in the sense that you must obey it, but it does leave open the possibility of two natural formations:

A group of boys is/are standing over there

On second thought, another possible ‘law of proximity’ is that modifiers (adverbs and adjectives) should be placed as near as possible to their referents in order to avoid confusion:

(X)The man gave me a sandwich who is sitting over there.
The man who is sitting over there gave me a sandwich

The modifying clause (who is sitting over there) should be placed near its referent (man)-- just in case we might think it is a sitting sandwich (somewhat personified).

sir, can I say about seventy to eighty percent of the students have or has improved?

can I also say a greater percentage of the students has improve?

70-80% of the students have…
70-80% of the water has…

‘Greater percentage’ is OK.

Sir, do i say: i was not one of those who was chasing her for tips
or i was not one of those who were chasing her for tips?