19.Not all events in history are as terrible as this, of course.　

18.However, in more recent times, most Americans remember what they were doing when the 　World　 　Trade　 　Center　　 in 　New York　 was destroyed by terrorists.　

17.Our teacher asked us to stop what we were doing and listen.　

16.Even the most everyday activities can seem important.　

15. This was one of the most important events in modern American history.　

14.People often remember what they were doing when they heard the news of important events in history.　

13.Beijng was made host to the 2008 Olympics.　

12.Liu Xiang won the gold medal at the 2004 Olympics.　

11.I was so tired this morning. It was difficult to get out of the bed.　

10.　 She didn’t thinking about looking outside the station.