I'm afraid i didn't understand what you meant by that))))) I'm not that good,
I'm studying the language now))))
I do apologize. My post was not appropriate for someone who is just learning English.
My point was there may be some idioms which can be slightly altered, while others would lose their meaning altogether.
Let's look again at the idioms I used.
"A bird in the hand (that is, held in my hands) is better than two in the bush (that is, out in the bushes or the trees)." This is an idiom which says that it is better to take what presents itself to you now rather than hold out in the hopes that you will gain more later. For instance, if you offer to buy my car for $1000 and I say no -- hoping that someone else may come and give me $2000--I may end up with no offers at all.
Could we change this idiom by making it plural? I would say No.
"A stitch in time saves nine." If we fix a rip in our pants (for example) when it is very small, it will keep us from having to fix a large rip later on. We might say this whenever we see someone who is procrastinating, rather than fixing a problem when it first comes up. For example, we should always fix the squeak in the car now before it turns into something worse.
Here, too, I would say that we can't change this into the plural without affecting the quality of the idiom.
My point, again, is simply that some idioms can be changed, at least slightly, while others can't.
Again, I'm sorry to have confused you with this. I hope this makes things clearer.
Before long you will become a master of English idioms. If you have another one you are wondering about, please share it here.