Here's why:
* Morpheme: The smallest meaningful unit of language.
* Bound morpheme: A morpheme that cannot stand alone as a word, but must be attached to another morpheme.
* Combination: Bound morphemes are always used in combination with other morphemes, either free or bound.
Examples of bound morphemes:
* Prefixes: "un-", "pre-", "re-"
* Suffixes: "-ing", "-ed", "-ly"
* Inflections: "-s" (plural), "-es" (possessive)
Examples of bound morphemes combining with other morphemes:
* "un-" + "happy" = "unhappy" (prefix + free morpheme)
* "walk" + "-ing" = "walking" (free morpheme + suffix)
* "cat" + "-s" = "cats" (free morpheme + inflection)
Let me know if you have any other questions!