be used是动词的被动语态。而used是过去式。或者过去分词。

  例如：1) Our time and money have been used.2）We should use our time to do something useful.

3) With the money used up，they had to hunt for a new job.

   be used to do something被用来做某事be used to something/be used to doing sth习惯于某事/习惯于做某事used to do something过去常常做某事。