SSC CGL 2025 Tier-I · 16 September 2025, Shift 2 · English Comprehension · Question 13 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 13 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

Change the following from active to passive: Someone must have tampered with the encryption keys.

(a)The encryption keys must have been tampered with.
(b)The encryption keys must have tampered by someone.
(c)The encryption keys must be tampered with by someone.
(d)The encryption keys must had been tampered with.

Answer

Why

Correct — A. The active verb is must have tampered with: a modal perfect (must have + past participle) on the prepositional verb tamper with.

The passive of a modal perfect is must have been + past participle:
must have tampered with → must have been tampered with

The keys become the subject. The indefinite agent someone is dropped, and with stays after the verb → option (a).

Why the others are wrong

(b)
The encryption keys must have tampered by someone. — must have tampered has no been, so it is still active in form and says the keys did the tampering. It also drops the with that tamper needs.
(c)
The encryption keys must be tampered with by someone. — must be tampered with loses have, turning a deduction about the past into a present deduction or a requirement. A voice change keeps the time reference.
(d)
The encryption keys must had been tampered with. — must had been breaks the modal rule: a modal is followed by the base form, so must have, never must had.

Concept

A voice change keeps the tense and the modal; what moves is the subject and the object. For a modal perfect the passive frame is modal + have been + past participle: must have been done, could have been seen.

A prepositional verb (tamper with, look into, laugh at) keeps its preposition in the passive, so the preposition ends up after the participle: the keys must have been tampered with.

The keyed sentence has no by-phrase. That is normal when the active subject is someone, people or they: by someone adds nothing, so it is usually left out.

Key facts

Modal perfect passive: modal + have been + past participle.
A modal takes the base form: must have, never must had.
A prepositional verb keeps its preposition in the passive: tampered with, looked into.
An indefinite agent such as someone or people is usually omitted in the passive.

Study next

Passive of modals: must be done vs must have been donePrepositional verbs in the passive: laughed at, looked afterModal perfects for past deduction: must have, can't have

Common traps

Dropping the preposition. The keys must have been tampered is incomplete, because tamper needs with.
Keeping have but forgetting been, which leaves the sentence active in form.

A modal is carried into the passive at 11 Sep 2024, 16:00, English Q.5 (He must deliver pizza, keyed Pizza must be delivered by him) and at 15 Sep 2025, 16:00, English Q.12 (may confer, keyed may be conferred).

The passive of tamper with, preposition kept, appears inside 18 Sep 2025, 12:30, English Q.23: had the evidence not been tampered with.

Related PYQs

No directly related past PYQ was found.

Topic: Active and passive voice — all 132 SSC CGL questions on it, every solved shift.