Ex1:1b had been

2c asked/had sold

3c had/was ringing

4b went/had had

Ex3:1c which

2b that

3d A and B

4d why

5a which

5c came/had cooked

Ex2:1 This is the women who works for samsung company

2 We are looking for the key which can open any locks

3 The wife whose son is performing on the stage feels very happy

4 The girl whom I was looking at was very beautiful

5 I don't like the boy whom Sue is going out with

1)

1- b

2 - c

3 - c 

4- b 

2)

1. This is the women who works for samsung company

2. We are looking for the key which can open any locks

3. The wife whose son is performing on the stage feels very happy

4. The girl whom I was looking at was very beautiful

5. I don't like the boy whom Sue is going out with

3)

1 - c 

2 - b 

3 - d 

4 - d 

5 - a 

5 - c