我需要通过递归重新定义单词function。我有2个辅助函数，但我无法真正将最后一个函数放在一起。有什么想法吗？

takeWord :: String -> String
takeWord  ""      = ""
takeWord (' ':xs) = ""
takeWord (x  :xs) = x : takeWord xs

dropWord :: String -> String
dropWord  ""      = ""
dropWord (' ':xs) =  ' ' : xs
dropWord (x  :xs) =  dropWord xs

words' :: String -> [String]
words' "" = []
words' (' ':xs) = takeWord xs : words' xs
words' (x:xs) =  takeWord (x:xs) : words' (dropWord xs)

此输入" Correct answer is this"的结果应为["Correct","answer","is","this"]。现在，我得到以下输出：["","","Correct","this","this"]