as green as grass 没有经验的；少不更事；无生活经验

【例句】
When he left his school and started his first job, he was as green as grass.
当从学校毕业，并开始了他的第一份工作时，他是没有经验的。

When he left his school and started his first job, he was as green as grass.
当从学校毕业，并开始了他的第一份工作时，他太缺乏经验了。