`6`. The only thing Peter interested in is why I did it.
`7`. The security prevented him from escaping.
`8`. Helen has played the violin for ten years
`9`. This car is only worth a few hundred dollars
`10`. She advised Linda not to listen to Jack
`11`. She allowed her son to go to Sa Pa with his friends at the weekend.
`12`. He didn't want to take part in the celebrations.
`13`. Do you mind not smoking in here ?
`14`. The tsunami made many people in this area become homeless.
`15`. I have one new American friend. At the first days, I found it was difficult to understand what he said but it's OK now.
`16`. The weather was not good enough for the children to go to school.
`17`. Do you mind helping me to take the books to the library ?
`18`. I really must have my car repaired soon.
`19`. If you hadn't helped me, I could never have succeeded.
`20`. Peter kept us waiting for 2 hours.