2.
1. has built
2. haven't seen
3. has organised
4. has written
5. haven't sold
3.
1. My friends have had lots of barbecues.
2. We have organised a jumble sale.
3. He has bought a raffle ticket.
4. My brother has collected second-hand books for the(cred ca acesta este cuvantul care nu apare in poza) bring and buy sale.
5. My mum has raised 2000 pounds for charity.