一般过去时的被动语态：was/were+过去分词例如：I bought a book yesterday.——A book was bought by me yesterday.一般现在时的被动语态：is/am/are+过去分词例如：We read English every day. —— English is read (by us) every day.情态动词的被动语态：情态动词+be +过去分词例如：You must hand in your homework today.——Your homework must be handed in today.
