31.  Hundreds of student volunteers for Bradley have been fanning out across the state to knock on doors and canvass support.

32.  I knocked on doors every day for a month.

33.  I knocked on doors.

34.  In his first year at Harvard, Al Gore was knocking on doors and shaking hands while running for freshman council.

35.  In short, the Americans are now knocking on doors that the Japanese government appears eager to open.

36.  It is the monotonous pounding that provokes neighbors to knock on doors, begging for the sound to please be turned down.

37.  Knock on doors.

38.  Lacewell is the first to admit that his background has allowed him to knock on doors in small towns across America in search of quality football players.

39.  Local and federal officers have already started knocking on doors in Florida, Texas and Los Angeles, among other places.

40.  Most of the candidates have sent out mailers and knocked on doors in the rushed campaign.