long since

例句：

1. 1.I have been working here for a long time.
   我已经在这里工作很长时间了。
2. 2.She has been away from home for a long time.
   她已经离开家很久了。
3. 3.The movie has been on the screen for a long time.
   这部电影已经上映很长时间了。