51.   Sometimes computer programs are introduced before the students are able to grasp the basic concepts of the lessons.

52.   Such a basic concept.

53.   The basic concept has the Muppets operating their own TV station, KMUP.

54.   The basic concept behind the new systems, currently available only to corporations, is that whenever travelers use credit cards their expenses are registered electronically.

55.   The basic concept calls for replacing private campaign money with public money, thus freeing candidates from potentially corrupting obligations to lobbyists and special interests.

56.   The basic concept of Kosovo as a temporary protectorate in the care of NATO peacekeeping soldiers and UN administrators is beginning to look like an unworkable contradiction.

57.   The basic concept of the production was promising, but it was undermined by excessive busyness.

58.   The basic concept has remained the same through the centuries.

59.   The basic concept of talk radio has been around for a long time.

60.   The basic concept, however, remains the same.