Use a hyphen to distinguish between words such as re-creation and recreation.
Hyphens can resolve similar ambiguities in such terms as re-form and reform, re-cover and recover, or co-op and coop.
Hyphens to separate double or triple letters
Hyphens are sometimes used to separate awkward double or triple letters in compound words (anti-intellectual, cross-stitch). Always check a dictionary for the standard form of the word.
Exercises:
The hyphen 1
The hyphen 2