Answer:
Pre-fixes go BEFORE a word:
Un-
Un-happy
Un-satisfactory
Un-explainable
Re-
Re-place
Re-live
Suffixes go AFTER A WORD:
Ment-
Arange-ment
Develop-ment
Ful-
Grate-ful
Force-ful
Explanation:
Pre-fixes go before words, and suffixes go AFTER words.
