1

Can we use both of variants and are they interchangeable?

  1. The house is said to have been built a century ago.
  2. The house is said to be built a century ago.
1

The first sentence is the correct one.

Consider what you get by changing the phrase "is said to be" to a simple "is". For the second sentence, you get

*The house is built a century ago.

Which is not a valid statement.

Not the answer you're looking for? Browse other questions tagged or ask your own question.