v.用来表示某人或某物即主语本身,用来表示某人或某物属于某一群体或有某种性质( be的过去分词 ),在,存在,不受干扰,去过了,be的过去分词
These files have been zipped up to take up less disk space.
这些文档已经进行了压缩,以节省磁盘空间。
The house seemed muted, hushed as if it had been deserted.
房子里似乎悄然无声,安静得好像已经没人在住一样。
It had once been the home of a wealthy nobleman.
这里曾是一个有钱贵族的宅邸。