In section 4.1: Positive Lookahead the regex is specified as: > (T|t)he(?=\sfat) which includes the "\s" for a white space. However in the explanation it states: > In parentheses we define a positive lookahead which tells the regular expression engine to match The or the only if it's followed by the word fat. Problem: Explanation is missing mention of the white space. Solution: Explanation should indicate that the regex requires a whitespace.