Explain the difference between back-formation and suffixation.
【正确答案】：①Back-formation is considered to be the opposite process of suffixation.
②As we know, suffixation is the formation of new words by adding suffixes to bases, and back-formation is therefore the method of creating words by removing the supposed suffixes.
③This is because many of the removed suffixes are not true suffixes but inseparable parts of the words.
