Bill was going out with another girl. That's the reason... he didn't marry Alice.
why / that / --- (reason)
This is the house in... I grew up.
(in) which (place). Other possibilities: This is the house where I grew up. / This is the house which I grew up in.
I spoke to the neighbour... dog keeps barking.
whose (possession, of a person)
I found a restaurant ... menu looks fantastic.
whose (possession, of a thing). Another possibility: I found a restaurant the menu of which looks fantastic.
They hired a lawyer ... reputation is excellent.
whose (possession, of a person).
Last Saturday I went to a party ... was very exciting.
which / that (subject, of a thing)
She has a son ... is a doctor.
who / that (subject, of a person)
She bought a book ... ending surprised everyone.
whose (possession, of a thing). Another possibility: She bought a book the ending of which surprised everyone.
That's the restaurant at ... we first met.
(at) which (place). Other possibilities: That's the restaurant where we first met. That's the restaurant which we first met at.
The reason ... she's happy is that she has just known she's pregnant.
why / that / --- (reason)
Joan is the student ... speaks four languages.
who / that (subject, of a person)
Christopher Columbus was the man ... discovered America.
who / that (subject, of a person)
I remember the time ... I lived and studied in Salamanca.
when / that / --- (time)
The country ... I spent my last holidays is Italy.
where (place). Other possibilities: which I spent my last holidays in is Italy. / Formal: in which I spent my last holidays is Italy.
The moment ... I met Paul is a moment I'll always remember.
when / that / --- (time)
She went to the bank ... is near the chemist's.
which / that (subject, of a thing)
I always remember the weekend... we went camping.
when / that / --- (time)
This is the dog ... I bought from the pet shop.
which / that (object, of an animal - thing)
Los Realejos is the village ... Carmen Luisa lived until she was 24.
where (place). Other possibilities: which CL lived in until she was 24. Formal: in which CL lived until she was 24.
2000 was the year ... I got my first job.
when / that / --- (time)
The bus ... goes to the airport leaves every 30 minutes.
which / that (subject, of a thing)
I haven't used the sweater ... I bought last month.
which / that (object, of a thing)