Change the following from active to passive: They were showing the movie at 7 pm.

Correct — C. The active verb is were showing: were + -ing form, the past continuous.

Its passive is was/were + being + past participle.
The object, the movie, becomes the subject. It is singular, so the helper is was.

They were showing the movie → The movie was being shown at 7 pm → option (c).

Why the others are wrong

• (a)
  The movie is shown at 7 pm. — Is shown is the simple present passive. The active sentence is in the past and in progress, so this option loses both the tense and the continuous sense.
• (b)
  The movie was shown at 7 pm. — Was shown is the simple past passive. It keeps the past tense but drops being, so the showing is no longer in progress at 7 pm.
• (d)
  The movie has been shown at 7 pm. — Has been shown is the present perfect passive: a completed action tied to the present. The given sentence is past continuous, so the tense changes.

In a voice change the tense stays the same. Only the verb's shape changes: the helper for that tense, then the past participle.

For continuous tenses the marker is being: is/are being shown in the present, was/were being shown in the past.

The helper agrees with the new subject. They were showing becomes the movie was being shown, because the movie is singular.

A vague agent such as they is usually dropped, so the passive needs no 'by them'.

Key facts

• Past continuous active: was/were + -ing form, as in they were showing.
• Past continuous passive: was/were + being + past participle, as in the movie was being shown.
• The passive helper agrees with the new subject: the movie was, the movies were.
• A vague agent such as they or people is usually left out of the passive.

Common traps

• Choosing 'was shown' because the tense is past, and missing that being is what keeps the action in progress.
• Keeping were from the active sentence, when the new subject, the movie, is singular and needs was.

No directly related past PYQ was found.