Study the relative clauses in the following sentences and see if you can 
tell the differences between relative clauses that refer back to similar nouns/ 
noun phrases.

They love their present house, which they bought last year.
The house which they sold to an American couple last year was 
still in very good conditions.
Right below us is San Francisco, where we first met.
San Francisco is a city where romantic stories often take place.
He just took a driving test which will make it impossible for him 
to go to sleep tonight.
This is David's first driving test, which he has been preparing for 
since half a year ago.
He failed his driving test, which must be discouraging.
In my opinion, Wall Street Journal is the most respected financial 
magazine, which sells over a million copies each issue.
Could you get me a financial magazine which has the longest history?
She reads financial publications, which is unusual for a 15-year-old.
The manager should decide who should take up his work when he is on 
leave. 
The manager should select those officers whom he authorizes to sign 
on his behalf. 
The manager should select those officers who he desires should sign 
on his behalf. 
There has been some argument about who should be authorized to sign 
on the manager's behalf.
The one person about whom many people have reservations is really 
new here.