Thebasicunitinthestudyofmorphologyis______.
Whathehaddoneis_______
ModernEnglishwordsman,woman,child,eat,fight,etc,originatefrom______.
Youngerchildrenarecurious________howthingswork，andmanyofthemwanttotakeaparteverythingwithintheirreach.
ThechildhoodofTomSawyerandHuckFinnintheMississippiisarecordofavanishedwayoflifeinthe()Mississippivalley
