Select the option that expresses the given sentence in passive voice. They have built a new bridge across the river.
- (a)A new bridge by them has been built across the river.
- (b)A new bridge has built across the river by them.
- (c)The river has been built a new bridge by them.
- (d)A new bridge has been built across the river by them.
Answer
Why
Correct — D. The active verb is have built, present perfect. The passive of a present perfect verb is has/have been + past participle, so "have built" becomes "has been built".
The active object, "a new bridge", moves into the subject slot. It is singular, so the auxiliary drops from have to has.
The agent phrase goes last, after the place phrase: has been built across the river by them — option (d).
Why the others are wrong
- (a)A new bridge by them has been built across the river. — The verb form is right and the placement is wrong. "By them" belongs at the end of the clause, after "across the river"; wedged between the subject and its auxiliary it breaks English word order.
- (b)A new bridge has built across the river by them. — Been is missing. "A new bridge has built" is still an active verb form, and it says the bridge did the building. The passive needs has + been + built.
- (c)The river has been built a new bridge by them. — "The river" is the object of the preposition across, not the object of "built". Only the direct object, "a new bridge", can be promoted to passive subject.
Concept
Changing voice moves the object into the subject slot and turns the verb into be + past participle, with the form of "be" carrying the original tense.
Present perfect active "have built" therefore becomes present perfect passive "has been built", and the auxiliary agrees with the new subject, not with the old one.
The doer, if it is kept at all, becomes a by-phrase and sits at the end of the clause. Nothing else in the sentence moves — "across the river" stays where it was.
Two of the wrong options are wrong on form and one on the choice of subject, so this item rewards a candidate who builds the passive before looking at the list rather than one who picks the option that reads most smoothly.
Key facts
- Present perfect passive is "has/have been + past participle".
- The passive keeps the tense of the active verb — only the voice changes.
- The auxiliary agrees with the promoted object: a new bridge has been built, new bridges have been built.
- The passive subject is the active verb's own object, so a noun sitting inside a place phrase — the river, after across — cannot be promoted.
Study next
Common traps
- Dropping "been" and leaving "has built", which passes unnoticed when read aloud quickly.
- Moving the by-phrase next to the subject instead of the end of the clause.
- Promoting a noun that is only the object of a preposition, such as "the river" here.
SSC gives the active sentence and asks for the passive; the tense of the active verb varies from item to item and settles the answer. English Q.15 of this paper does the same job in the present continuous, and 13 Sep 2024, 12:30, English Q.1 converts another present perfect, "The children have made the box".
Related PYQs
No directly related past PYQ was found.