WORK - WORK ON

- Working in = the field of
I work in a accouting corporation. (usually for business area )

You wouldn't say that you work in a corporation, you'd say at or for them. It is correct to say in when talking about which part of the company you work for, or if you are talking about a place. So:

• I work for an accounting company.
• I work at a famous legal firm.
• I work in the accounting department at Samsung.
• I work in the cafeteria.
• I work in London.
• I work for Samsung in London.

(Also, note that it's an accounting corporation, not a accounting corporation.)

- Work at = a place
I work at Samsung. ( usually for specific name of company )
I work at a factory.
I work at Samsung.
This is correct. It would also be correct to say I work for Samsung.


- I work for my boss. ( usually for certain person )
This is OK grammatically, but feels odd to me because it seems rather tautological: by definition the person you work for is your boss, so there's no need to say so. It would be better to indicate the specific person who is your boss:

I work for him
I work for Amanda Jones
I work for Dr Jenkins
I work for the CEO (you'd only say this if you report directly to the CEO)
(Of course if you are self-employed, or unemployed, then you wouldn't be talking about working for somebody in the first place.)

- Working on = a goal

I am working on my BA

Cambridge Dictionary's definitions are good as far as they go:

Work on: to spend time repairing or improving something.

I would expand that: to spend time and effort repairing, improving, or completing something. It usually applies to an object or task. "I'm going to work on my homework." or "I'm going to work on my car."

Note that "work on" can also have a different meaning, referring to the environment in which labor is performed: "I am a fisherman; I work on the ocean." The actual work involves fish and fishing equipment. The location or environment is the ocean, the person doesn't actually do anything to the ocean, itself.

Work at: to try hard to achieve something.

I would expand that: to try hard to improve or achieve something. It usually applies to a skill or characteristic, which is often expressed in the form of an action or condition. "To become better at English you need to work at it." or "I need to work at my piano playing."

Note that "work at" can also have a different meaning, referring to the location of employment: "I work at McDonald's".

	Work in – work at – work on
Mas trabalho nas pistas de boliche.	But I work at the bowling alley.
Eu só trabalho no Hospital Regional de Buffalo.	I just work at Buffalo Regional.
Ninguém tem vindo trabalhar para a empresa à mais de uma semana.	Nobody has come to work at this company for over a week.
Você... Vai trabalhar com minha equipe a partir de agora.	You... work in my team from now on.
Não deu certo em Jerusalém.	IT DIDN'T WORK IN JERUSALEM.
Não trabalha no Pentágono?	YOU DON'T WORK IN THE PENTAGON?
Precisa melhorar seus modos com crianças.	You really need to work on your child skills.