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They expected us to build the road.

put into passive:

They expected us to build the road.
is the version I think is correct.

What about:
The road was expected to be built by us.

Any suggestions or comments?
Thanks for you help !!
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They expected us to build the road. (active)
We were expected to build the road. (passive)
Comments  
Students: We have free audio pronunciation exercises.
Tokyo manufactures this car in Japan.convert in active voice
anonymous Tokyo manufactures this car in Japan.convert in active voice

This is already active. A possible passive version would be "This car is manufactured in Japan by Tokyo". (By the way, did you mean Toyota rather than Tokyo?)

"The road was expected to be built by us" is a possible answer too.

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Teacher BeaThe road was expected to be built by us" is a possible answer too.

Not really. A personal pronoun as object of a prepositional phrase used for passive agent is a non-native construction—or at best, very poor style.