what is the difference between "come to use/rest/know/etc " and "come into /rest/know/etc "
“come to” followed by a verb, as in your first set of examples, can mean two different things:
It can mean physically move to a place in order to do that action. For example, as a reason for entering a library, you could say “I’ve come to use the free Internet access”. This meaning is unlikely with “know” and other stative verbs.
It can describe a gradual change which results in you doing something now that you didn’t do in the past. For example: “I’ve come to know her quite well” means that at one time you didn’t know her very well, but gradually you have become acquainted.
“come into” cannot be followed by a verb, so your second set of examples are not correct. Compare with "come in to ", which is similar to the first meaning of “come to” above, but with more focus on moving inside something (such as a building).
how to explain “come into use/effect/ leaf” ?
“use”, “effect” and “leaf” are nouns in that case. This non-literal sense of “come into ” works only with certain special nouns, such as the ones you mention. You can think of these as set expressions.
However, we came into an agreement each other yesterday
I think it is correct Dozy? with style?
Well, what should it be?
What should what be?
I wrote it, Bev denied and said 'No", it does mean she differs so that what the actual format should be?
Listen, this structure is nothing for me to know from a good grammar book or Web star dictionary. So I protest twisting when something is serious. I asked this question seriously as I didn’t make any joke here.
Our respected teachers should understand this and that, conflict just arises from this ways.
Hope we can understand all what I wanted to mean. I never make any joke in my study period that was why I secured BD. Govt. scholarship in my 12 years education finishing time though I am not a good student at all!