be done是被动语态，不是时态。且be done一般表示被动语态中的一般现在时态。把主动语态的谓语变成被动语态的be+ 过去分词，时态要与原句保持一致。

相关介绍

例句：

They will build a new bridge over the river. (主动)

A new bridge will be built over the river. (被动)

My aunt invited me to her dinner party.

I was invited (by my aunt )to her dinner party.