sentence: He is best known as the network's White House Correspondent (1977–1989 and 1998–99) and as a panelist and later co-anchor of the network's Sunday program, This Week.
modified: fix grammar: He is best known as the network's White House Correspondent (1977–1989 and 1998–99) and as an panelist and later co-anchor of the network's Sunday program, This Week.