I have a friend whose husband travels a lot. I have a friend whose husband travels a lot.
Whom is a pronoun, whose can be a pronoun or a determiner and where is an adverb.
There are several different ways to construct sentences with these pronouns. Here are some examples:
These are the people whom I met at the conference.
This is my friend whose parents are Canadian.
My sister still lives in the town where we were born.
Whom is used to talk about people and is sometimes an alternative to who and that.
Whose refers to belonging and association and can be used with people or things.
Where is used to talk about places.
=====Whom=====
Note that this is pronounced /hu:m/.
We can use whom or who in this kind of sentence:
The client whom/who we met in London is coming to see us next week.
This is because 'The client' is the object of the verb 'met' and the subject of the verb 'is coming'.
In contrast, we cannot use whom in this sentence:
My sister whom lives in Paris is an architect. 
My sister who lives in Paris is an architect. 
Because 'My sister' is the subject of both the verb 'lives' and 'is'.
If there is any doubt, it is better to use who because it is much more common than whom - both spoken and written.
=====Whose=====
Note that this has the same pronunciation as 'who's' - /hu:z/.
We use whose in relative clauses. It replaces the possessive adjectives 'his', 'her', 'its' and 'their' and enables us to use one sentence instead of two/
Note that it can be used to refer to what 'belongs' to a person or a thing:
I have a friend. Her children are the same age as mine.
= I have a friend whose children are the same age as mine.
What's the name of the man whose car you borrowed?
I work for a company whose head office is in Lyon.
These sentences show the difference between who and whose:
I had lunch with a man who works in Lyon. [He works in Lyon.]
I met a man whose sister works in Lyon. [His sister works in Lyon.]
We use where in defining relative clauses to avoid repeating the name of a place and so that we can use one sentence instead of two. It has the meaning of 'there' or 'in that place'. For example:
| 'Where' in relative clause | Meaning |
|
The village where I was born is in the South of France.
|
The village is in the South of France. I was born there/in that village. |
|
I want to live in a town where there are lots of shops, theatres and museums. |
There are towns with lots of shops, theatres and museums. I want to live in this kind of town.
|
=====Examples=====
Is that the building whose roof was damaged?
We like relaxed, informal restaurants where we can get good food and wine at reasonable prices.
"Is this your first visit here?" "Yes, it is. But I have a friend whose sister works here."
There is someone whom I would like to bring into this team.