has been lost是什么時態

　　That herbal prescription has been lost to posterity.

　　這種藥方沒能傳下來。

　　Yet plenty has been lost too, even in cultures that still live to eat, take Italy.

　　然而，人們也失去了許多，即使是在那些仍然為吃飯而活的文化中也是一樣，拿意大利舉例來說。

　　Moran says one of the problems with jazz today is that the entertainment aspect of the music has been lost ．

　　莫蘭說,現在爵士樂的一個問題是,失掉了音樂的娛樂性。

　　That ancient work has long been lost.

　　那部古書久已佚失。