自从

例句：

1. 1. Since I moved to the city, I have been working in a new company.
   自从我搬到城市，我一直在一家新公司工作。
2. 2. She has been studying English for three years since she started college.
   她自上大学以来已经学习英语三年了。
3. 3. He has been waiting for his friend for an hour since they left the meeting room.
   他从会议室离开后已经等了他一个小时的朋友了。