live——outlive

　　door——outdoor

　　over-：too much；above；additional

　　head——overhead

　　time——overtime

　　poly-：many

　　centric——polycentric

　　syllabic——polysyllabic

　　post-：later than；after

　　graduate——postgraduate

　　war——postwar

　　pre-：before；in advance

　　pay——prepay

　　war——prewar

　　pro-：in favor of，supporting

　　America——pro-America

　　abortion——pro-abortion

　　re-：again；back to the former state

　　unite——reunite

　　use——reuse

　　self-：by means of oneself or itself；of，to，with，for，or in

　　oneself or itself

　　employed——self-employed

　　taught——self-taught

　　semi-：half；partly

　　circle——semicircle

　　final——semifinal

　　step-：not by birth but through a parent who has remarried

　　mother——stepmother

　　children——stepchildren