You had to figure the Cubs were in for a daily double?sworth of trouble Tuesday, even if the San Francisco Giants rodeinto town as the lowest-scoring team in the National League. The Cubs and the Giants had to play aday-night doubleheader, the result of a rainout at Wrigley Fieldlast month. It just so happened that with the way the pitching rotationturned, the Cubs had to throw their, gulp, Nos.5 and 6 starters.