To build a sentence by deciding whether a prepositional phrase is an adjectival or an adverbial.

Hello my friends.

First of all, I am really proud of being a member of this big English community. It is very nice to discuss an idea, find a solution to problems.

I've been studying on how to put prepositions in a sentence correctly.

When I put them on the bad word order, meaning of sentence changed.

Today, I decided to trust my feelings/ears/eyes while putting them. Because there is no rule about it and especially when it comes to relative clauses' position, there is never a rule.

I am writing some sentences with their explanation(my thoughts) below.

1-) I have a computer in my office that you can use for your works.

"In my office" is answering the question "Which computer?" rather than "Where do I have?"

That's why I am thinking that it refers to "a computer" and why they should be together.

2-) He continued the war that would never finish against his enemies.

Some people said: "Oh no! "Against his enemies" is describing "the war". You should not separate them."

But I don't think like them. It may refer okay but it doesn't mean that it doesn't refer to the verb(continue)

It never seems to be good "the war against his enemies that would never finish" (what would never finish? the war or his enemies?"

3-) I received an extremely important letter which I had been looking forward to from the university.

In this case, I believe that it would be also correct

"I received an extremely important letter from the university which I had been looking forward to."

It depends on what you want to emphasize in this sentence.

The most important thing about "the letter" is "the university" or "I had been looking forward to"

If the important one is "the university", you can say "the second one",

but if it is you had been looking forward to, you can say example three.

What do you think about my three different examples?

Thank you very much for everything!