[Haskell-beginners] How to tell haskell that 'a' is 'a' ?

Hi all, skips :: [a] -> [[a]] skips xs = go 1 [] where go :: Int -> [[a]] -> [[a]] *-- Compiles if i remove this line* go n acc | n > (length xs) = acc | n == 1 = xs : (go (n+1) acc) | n < 1 = [] | otherwise = (everyN n xs) : (go (n+1) acc) everyN :: Int -> [a] -> [a] everyN n xs = case (drop (n-1) xs) of y:ys -> y : (everyN n ys) [] -> [] How can i tell haskell compiler that a is the sub program if the same as a in the main program? -- Best Regards, Boon Hui