The postbox is usually emptied...
The stamps are usually postmarked...
The letters are usually sorted...
The mail is usually loaded...
The mailbags are usually unloaded...
The bags are usually taken...
The letters are usually sorted...
The letters are usually delivered...
Present Simple, Passive Voice:
* Подлежащее в ед.числе + is + usually + V3 / Ved
* Подлежащее во множ.числе + are + usually + V3 / Ved
