Cover letter: work in/work for/work with/work at

Question

I understand how these work:

• I work in IT.

• I work at Google.

• I work for Google.

• I work with computers.

But how about these? To tell someone if I get this job, I would gain experience.

1. I will gain experience by working in your firm?
2. I will gain experience by working at your firm?
3. I will gain experience by working for your firm?
4. I will gain experience by working with your firm?

I am not sure quite now. Which of the above are preferred? #4 is slightly less my preference because "with" gives me the implication that I am working in a joint partnership (business-business), although one can argue a worker works with employer.

Answer 1

I'd use "to work for"

According to the Free Dictionary

work for someone

1. to be employed by someone

to work at remarks the place. You can work at Google's cafeteria and you may be hired by Google but if you want to remark that you're a software engineer, I'd use "to work for".

to work with, as you have stated, got a sense of business-business relationship, it seems to denote that you work for a company that has established a temporary partnership with Google.