答案:AstemisoftenusedinLINGUISTICSaspartofaclassificationofthekindsofELEMENTSoperatingwithinthestructureofaWORD.ThestemmayconsistsolelyofasingleROOTMORPHEME(i.e.a“simple”stem,asinman),oroftworootmorphemes(i.e.a“compound”stem,asinblackbird),orofarootmorphemeplusaDERIVATION/ELAFFIX(i.e.a“complex”stem,asinmanly,unmanly,manliness).Allhaveincommonthenotionthatitistothestemthatinflectionalaffixesareattached.DavidCrystal]