We kept up a correspondence for many years.
我们保持了很多年的通信联系。
Have you kept in contact with any of your friends from college?
你和你大学里的朋友还保持联系吗？
Your application will be kept on file.
你的`申请书将存档。
The thought kept going round and round in her head.
这个想法一直萦绕在她的心头。
He kept us at it all day.
他让我们不停地干了一天。