Read the Learn this! box. Complete the rules. (Đọc phần Learn this! và hoàn thành các quy tắc.)

LEARN THIS! The passive

1. We form the passive with the verb 1 _____ and the 2 _____ of the main verb. The object of an active verb can become the 3 _____ of a passive verb.

They haven’t found a cure for colds yet. (a cure = object)

→ A cure for colds hasn’t been found yet. (a cure = subject)

2. If we need to mention the agent, we use 4 _____.

Enormous public baths were built by the Romans.

3. We use the passive:

a. when we do not know (or do not want or need to say) who does something.

b. for more formal language, e.g. for processes.

First, the coffee beans are dried. Then they are roasted.

c. when we want to focus on the person to whom the action is done, not the person doing the action.

4. We use the 5 _____ and past continuous forms of the passive, but we do not use other continuous forms.

Hygiene is being improved. 

→ Hygiene has been being improved. X

→ They have been improving hygiene.