Select the correct active form of the given sentence. Why was such a letter written by your brother?

Correct — B. Read the tense off the passive first. Was written is was + past participle: the simple past passive.

In the active, the doer, your brother, becomes the subject, and a simple past question needs did + base verb: 'Why did your brother write such a letter?'

Why stays in front and 'such a letter' becomes the object → option (b).

Why the others are wrong

• (a)
  Why was your brother writing such a letter? — Was writing is past continuous, whose passive would be 'was being written'. Choosing it changes the tense.
• (c)
  Why does your brother write such a letter? — Does write is simple present, whose passive is 'is written'. The given sentence is in the past.
• (d)
  Why had your brother written such a letter? — Had written is past perfect, whose passive is 'had been written'. The given passive has neither had nor been.

A voice change keeps the tense and swaps the roles: the agent after by becomes the subject, and the passive subject becomes the object.

Match each passive to its active:
was written → wrote, or did write in a question
is written → writes, or does write
was being written → was writing

In a wh-question the question word stays first, and a simple past question takes the helper did.

Key facts

• Simple past passive: was or were + past participle (was written).
• A simple past active question uses did + base verb: Why did he write?
• Past continuous passive: was or were being + past participle (was being written).
• Past perfect passive: had been + past participle (had been written).

Common traps

• Choosing 'was writing' because it keeps the was of the passive — was writing is past continuous
• Choosing 'had written' because the letter was written earlier — the passive has no had, so the tense is simple past

No directly related past PYQ was found.