Reduced relative clauses

Although it is not possible to omit the relative pronoun in the subject relative clauses that we have just looked at, we can, if we want, omit an even larger piece of the relative clause and still retain a grammatically acceptable sentence. Using the examples from above, we can say:

• I can't find my notebook containing all my addresses.
• She has never met the lecturer leading today's seminar.
• The tall man standing by the bar is my uncle.
• The newspaper first reporting the incident is being sued.

This is usually referred to as a reduced relative clause and can only be applied to subject relative clauses not object relative clauses.
The most obvious feature of this type of reduced clause is that the relative pronoun is left out and the verb following the noun always ends in -ing. The second, but perhaps not quite so obvious feature is that the tense of the verb in the original relative clause is not taken into account. Note how the verb tenses varied in the original sentences:

• I can't find my notebook that contains all my addresses. (Present Simple)
• She has never met the lecturer who is leading today's seminar. (Present Continuous)
• The tall man who was standing by the bar is my uncle. (Past Continuous)
The newspaper which first reported the incident is being sued. (Past Simple)

These -ing forms of the verb in a reduced relative clause are called non-finite verbs, that is, they are not marked in any way for tense. Here, the tense is carried only in the verb of the main clause.
So, to sum up so far, subject relative clauses cannot lose their relative pronoun, except when the whole relative clause is reduced to a non-finite -ing verb form. Object relative clauses can lose their relative pronoun, but cannot form reduced relative clauses.
Now consider the following set of sentences:

• The information given in the brochure is wrong.
• The criminal picked up at the airport was taken into police custody.
• We saw the new play written by Tom Stoppard at the Old Vic.
• The second piece played by the orchestra was very well received.

These are also examples of reduced subject relative clauses, but this time the word immediately following the noun which is being described is not an -ing type finite verb but a past participle; these are in bold.
The difference here is that those reduced relative verbs ending in -ing (looked at above) stand in for active verbs, while the past participles replace passive verbs and, as with the former type, they can replace almost any tense.
However, continuous tenses are usually replaced by being + past participle, so in the last sentence we might want to bring it into the here and now by saying: The second piece being played by the orchestra was especially commissioned. Among the possibilities for the full relative clauses for each of the above examples are:

• The information which is given in the brochure is wrong.v
• The criminal who was picked up at the airport was taken into police custody.
• We saw the new play that was written by Tom Stoppard at the Old Vic.
• The second piece which was played by the orchestra was very well received.