11.   For many Internet users, the medium simply provided an immediate way to share their own personal experiences of a national tragedy.

12.   For others it was a national tragedy.

13.   From that choice, a national tragedy evolved.

14.   I am President George W. Bush, doing and saying the right things in the face of an unprecedented national tragedy.

15.   In the midst of a profound national tragedy, Larry and Sharon Elimon have found proof that life can carry on.

16.   It has survived national tragedies.

17.   Looked at that way, the performance of our journalists can be seen as a kind of national tragedy.

18.   Many people and businesses are flying their flags at half-mast, a symbol reserved for the death of high-ranking politicians or a national tragedy.

19.   Not a flag attached to a national tragedy.

20.   Of course, no one in Silicon Valley would dare to even suggest that the tech industry is poised to profit from a national tragedy.