1. 动词 → 名词（最高频）
-tion / -sion
act→action, educate→education, decide→decision, discuss→discussion
-ment
develop→development, agree→agreement, improve→improvement
-ance / -ence
differ→difference, depend→dependence, appear→appearance
-er / -or（人 / 设备）
operate→operator, employ→employer/employee
2. 名词 → 形容词
-ful：care→careful, hope→hopeful
-less（否定）：care→careless, useless
-ous：danger→dangerous, fame→famous
-able：accept→acceptable, suitable
3. 形容词 → 副词（拼写易错）
一般 + ly：quick→quickly
y 结尾变 i+ly：happy→happily, easy→easily
le 结尾去 e+y：simple→simply, possible→possibly
特殊：true→truly, full→fully
4. 动词后缀（使役）
-en：wide→widen, deep→deepen
-ify：simple→simplify
-ize：modern→modernize
5. 否定前缀
un-: unfair, unable
in-/im-: impossible, incorrect
dis-: disagree, disappear
6. ing/ed 分词形容词（每年必考）
doing（修饰物，令人…）：interesting, surprising, exciting
done（修饰人，感到…）：interested, surprised, excited