"After long accumulation(a long period), they will gradually form a habit, which is to be dependent on the charity given by the rich."
How to say that properly in English?
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
They will gradually form a habit of dependence on charity given by the rich.
The meaning of "After long accumulation" and "(a long period)" are both essentially contained in "gradually" - i.e. that it will take time, rather than being instantaneous. We don't want to say the same thing three times, so I chopped that off.
Side note, here - "accumulation" means "build up over time", and probably wouldn't be appropriate here. You could talk about dust accumulating in an attic, for example.
...they will gradually form a habit, which is to be...
This grammar is incorrect. You'd use a comma followed by "which is" to define a word. For example, "He contracted HIV, which is a disease affecting the immune system". When explaining that people have a specific habit, you use "of", as in "I have a habit of correcting people's English".