‘”Going back to years past and things that have happened, we had opportunities and let them slide . . . ,” said Evans, the Bills’ leading receiver, though he dropped that thought in mid-sentence and shrugged. The four consecutive Super Bowl losses in the early 1990s, the late-season rush to the 2004 playoffs that fell short with a last-week loss, even that victory against Dallas last season that inexplicably melted into another head-shaking defeat . . . they are all part of the package up here. So Evans knows the way the first half of the 2008 season has unfolded is a bit disconcerting. Four straight wins pumped life into these ferociously proud and unpretentious fans, but three sloppy losses in four games have left them wondering just what to make of the team’s 5-3 record.’