1.The man went to the police station.His car was stolen(whose)
2.She bought a smartphone.It has NFC and 5G technologies(that)
3.I have found the letter.I have been looking for it(which)
4.She has a boyfriend.His mum is a well-known teacher(whose)
5.The student asks a lot of questions.He sits in the corner of the room(who)
6.The problems need to be addressed. Homelessness is one of them(that)
7.There's the restaurant.We had dinner at the restaurant last night(where)
8.Yesterday I met a man.He works in an office by day and drives a taxi by night(who)
9.The new reference books are very good.I borrowed them from the library(which)

1. Soil pollution causes the death of the trees
=> Soil pollution leads 
2. English is an official language in the USA 
=> People in the USA 
3. A famous painter painted that picture 
=> That picture 

1. Do exercise everyday and you will be healthy.
=> If