41.   At the Public Service Commission, William Voight, assistant manager of telecommunications, compared Caller ID to someone knocking at your front door.

42.   Back I went to knock at the farmhouse door.

43.   Between those, a tree trimmer knocked at the door to say he was working on the block and had spied some deadwood in my trees.

44.   A few minutes later someone knocked at the door again.

45.   A few nights later a state child abuse investigator knocked at his door.

46.   A guardsman knocked at the door.

47.   But Death keeps knocking at her door.

48.   But he said he was having difficulty accommodating all the people knocking at his door, especially those in the market for reasonably priced homes.

49.   But four months later he knocked at her front door.

50.   But Markman will not leave investors knocking at the door.