Indicates that object relative (O) clauses are learned after subject relative (S) clauses. Shows that children did not reliably comprehend O-clauses until nine years of age, two years after S-clauses. Suggests the need to attain a level of operational thought before O-clauses can be understood. (RL)

Two experiments showed that functional completeness--the explicit propositional surface realization of deep-structure clause relations--isolated effective and integral comprehension units, which definitions of comprehension units couched in levels of syntactic structure failed to do. (Author/RL)