[Grammar] at / in the office / hospital / school / etc

[tyrp]

Hello!
What's the difference between 'at' and 'in' with the words 'hospital', 'office', 'school', 'firm', 'company' if any? Do they bring any difference in meaning or is only one of them correct with some of these words?
E.g. He works at (the?) university (will the U be capital?) / at school / at the office / at the firm / at the company.
Can we use 'in' in all the cases above? Thank you so much!!!

 

[Champleon]

Hello,
Warning!: I'm not a teacher.

At (occupation, organization, place of work…)
In (kind of building, the inside of a building, the building itself…)

She is at hospital (she works there)
She is in hospital (she is ill)
We also may be working in a factory. However, if we are at hospital, school, the office, the firm or company premises; we are working there.

Your E.g. He works at university…

You cannot use “in” instead of “at” with any of the sequenced words, with the exception of the word “hospital”, bearing in mind the difference in meaning mentioned above.

 

[tyrp]

Thank you so much, Joaquin Garcia Navarro. One last thing concerns that word 'hospital' again: do we not use 'the' with it when talking about the activity not typical of it (not being ill, but working there)?
E.g. He is in hospital (ill). She works at the hospital. She is at the hospital now, working.
Do we not need 'the' here? Thank you again!

 

[Rover_KE]

You need 'the' after 'at' in the above examples.

 

[tyrp]

Thank you, dear Rover_KE. What about the original post and problem? Will you kindly help me there as well?)

 

[Rover_KE]

Each of the locations you mention needs a separate thread. There are too many variations to consider all at once.