Grammar - Active and Passive Voice (Perfect Tense and Modals)

Compiled from Grammar Builder Book 3

The rules are:

1. When changing a sentence to the passive voice from the present perfect tense, the perfect tense or the future perfect tense, we have to change the verb in these ways:

a)    Present perfect: has/have + been + past participle of verb

·         John has encouraged the children to exercise more often. (Active)

·         The children have been encouraged to exercise more often. (Passive)

b)    Past perfect: had + been + past participle of verb

·         Tim had told Mrs Johnson about Peter’s arrival before I called her. (Active)

·         Mrs Johnson had been told about Peter’s arrival by Tim before I called her. (Passive)

c)    Future perfect: will have + been + past participle of verb

·         By Monday next week, all the children will have finished all the food. (Active)

·         By Monday next week, all the food will have been finished. (Passive)

2. When changing a sentence with modals such as can, may or must from the active voice to the passive voice, we have to change the verb in these ways:

            Can + be + past participle of verb

              May + be + past participle of verb

              Must + be + past participle of verb

• The price of this apartment can be estimated by the company.
• This problem may be discussed at the next meeting.
• All the doors must be locked before we go out.