John is now with his parents in New York, it is already three yearssince he was a teacher
约翰目前和爸爸妈妈一块住在纽约,他不当教师已经三年了.
since 后面假如为持续动词，时间根据动词结束时算起，请问下面的怎么样讲解？
Since I was young, I’ve noticed changes in people’s hairstyles,clothes, facial expressions, behaviors.
自我小时候，还是我小时候结束以来……
若 since 后接持续性动词的一般过去时，从句的时间一般应从持续性动作结束时算起。正如你的句子：
John is now with his parents in New York, it is already three yearssince he was a teacher.
约翰目前和爸爸妈妈一块住在纽约,他不当教师已经三年了。
再如：
He has never come to see me since I was ill. 自从我病好以来，他还从将来看过我。
He has never come to see me since I lived here. 自从我离开（即没住在）这里以来，他还从将来看过我。
但此使用方法有少数状况是例外，譬如不包含以下状况：
since I was a child
since she was a young
since I was born
since he was born
……
