The key answer of exercise 3

a)

1. 've never owned
2. hasn't saved
3. charged
4. didn't inherit
5. haven't been
6. 've never used
7. did your TV cost
8. didn't have
9. have you lived
10. earned

b)

1. did; buy; passed
2. did; borrow; have; spent
3. Have; found; has; agreed
4. Have; lent; needed
5. Has; made; called

c)

1. Have you ever bought a house?; When did you buy it?
2. Have you ever found any money on the street?; How much did you find?
3. Have you ever used contactless payment?; Where did you use it?
4. Have you ever paid for a meal for a lot of people?; Why did you pay for it?
5. Have you ever stayed in an expensive hotel?; Who did you stay there with?
6. Have you ever raised money for charity?; How much did you raise?