2 activity.

Passive Voice.

The passive voice in English follows the general structure: Subject + Verb to be + Verb in participle + Object. For example
 - The structure was elucidated by Watson and Crick
To pass sentences from the active voice to the passive voice, simply:
1) Change the order of the subject and the object.
2) Add the auxiliary "to be" in the verb tense of the active voice.
3) Add the participle of the main verb.

form:

Basic steps to form the passive voice:
The object of the active becomes the subject of the passive.
We add the auxiliary “to be” – “is/are”
when the main verb of the active is present, and “was/were” when it is past.
In negative or interrogative sentences the auxiliary “to do” is replaced
by “to be”: 
- do(n’t) / does(n’t)
become is(n’t) / are(n’t); 
- did(n’t) becomes was(n’t) or
were(n’t).
We turn the main verb of the active into the past participle.
If we need or want to add the agent of the passive, we must use “by”.