George and Joan LIVE (live) in a small house in London. Right now they ARE STANDING (stand) in the sitting room of their house. They HAVE JUST COME (just come) back from a holiday in the country . They ARRIVED ( arrive) at the house five minutes ago.
"What HAS HAPPENED (happen)?" said Joan, as she LOOKED (look) round at the untidy room. "Someone HAS BEEN (be) in the house. They HAVE TAKEN (take) everything out of the cupboards and THREW (throw) it on the floor. Look, George, they HAVE BROKEN (break) all those glasse
Why is it "threw" instead of "thrown"; why was the past simple used instead of present perfect, I think it would be logical to be present perfect, she is discovering what happened it is more present than past.
http://www.english-grammar.at/online_exercises/tenses/all_tenses3.htm This comes from T026-Back from the holidays - All Tenses