Explanation

Present Indefinite Tense

Active Voice: Subject + Verb + Object

Passive Voice: Object + is/am/are+ third form of a verb + by + subject.

Explanation

 "They had eaten dinner before the movie started" is in the past perfect tense 

it indicates a completed action before another past event

indicate an action (eating dinner) that was completed before another action (the movie starting) in the past.

Explanation

Past Indefinite Tense 

Active formula: Subject + past tense form of the verb + object

Active: The police inquired into the case.

Passive formula: Object of the active sentence + was/were + past participle form of the verb + by + subject of the active sentence

Passive: The case was inquired by the police OR The case was inquired into by the police.

Explanation

The preposition since is used to show point of time e.g. Since 2015, Since May etc.

 The preposition for is used to show period of time e.g. For 3 days, For one hour etc.

Explanation

Past Perfect Tense: Had

Past Continuous Tense: Was/Were

Past Perfect Continuous Tense: Had been

Past Indefinite Tense: Verb 2^nd form

Explanation

Note: There are some verbs which never follow preposition “by” they have their own fixed preposition when the sentence is changed into Passive Voice.

Explanation

We use the simple present tense: An apple falls down.

Falls is the present tense of the verb "fall," indicating the action of the apple descending to the ground.

Explanation

Note:- While covering active into passive both parts should be made into passive.

Active Voice (Part 1): He took me to hospital.

Correct Passive Voice: I was taken to hospital by him.

Active Voice (Part 2): And the doctors operated me.

Correct Passive Voice: And operated by the doctors.

Present Indefinite Tense

Active Voice: Subject + Verb + Object

Passive Voice: Object + is/am/are+ third form of a verb + by + subject.

Explanation

Past perfect: Had

Present perfect: has/have

Future perfect: Will have/Shall Have

Explanation

Certain words when used in “Active Voice”  are not followed by any preposition.

“Accompany, affect, consider, compromise, emphasize, resemble, ensure, attack, invade, order, reach, describe, discuss, tell” etc.

The prime minister emphasized the matter.