４．動詞の語尾に『or』を追加する場合
vend → vendor(vender)
sail → sailor
act → actor
direct → director
contract → contractor
edit → editor
assess → assessor
counsel → counselor
profess → professor
５．動詞の語尾の『e』を削除し、『or』を追加する動詞
composite → compositor
supervise → supervisor
６．動詞の語尾が『ate』で終わっていて、最後の『e』を削除して『or』を追加する場合
commentate → commentator
communicate → communicator
terminate → terminator
translate → translator
operate → operator
coordinate → coordinator
estimate → estimator
negotiate → negotiator