or表示人的后缀的单词：
doctor 医生；
actor男演员；
agitator鼓动者；
ambassador大使；
author作家；
collector收集家；
compositor排字工人；
conductor售票员；
conqueror征服者；
creator 创建者
Doctors still don't understand much about the disease.
医生对这种疾病还不太了解。
Doctors still don't understand much about the disease.
医生对这种疾病还了解不多。
Who's the author?
作者是谁？
As the author of the proposal I cannot agree with you.
我作为提案的发起人不能同意你的意见。
The author has condensed a great deal of material into just 100 pages.
作者在短短100页中浓缩了大量信息。
温馨提示：
