5. 含情态动词的被动语态：情态动词 + be + 及物动词的过去分词。其中的be不能再作任何变化了。如：

⑦ Old people must _______.

A. be spoken to politely  B. speak to polite  C. be spoken politely  D. speak polite

⑧ Food and drink should _______ to bring into the reading room.

A. allow              B. allowed        C. not be allowed     D. not be allowing

    (Keys: 1―8 CDBCDBAC)

首先将主动语态的宾语变为被动语态的主语，然后将谓语变为被动语态，最后将主动语态中的主语放在介词by的后面。如：

A lot of people speak English. →English is spoken by a lot of people.

在将主动语态变为被动语态时，要注意以下几点：