English monolingual and Spanish/English bilingual children in kindergarten and first grade in 11 states were administered two tests from the EL CIRCO (CIRCUS) battery. The purpose of the study was to determine comparative acquisition of English grammar for kindergarteners and first graders and for bilingual and English monolingual children. Data were sought to support or refute general hypotheses of language acquisition. Data indicate that: (1) comprehension precedes performance in the acquisition of verbal inflections for tense, and tenses are mastered in a specific order; (2) children distinguish between third person possessive adjectives of gender (his and her) before those of number (his and their); and (3) the active voice and the concept of agent are acquired before the passive voice and the concept of object (agent-object relationship in embedded sentences and passive voice were undifferentiated in bilingual children tested). Data do not support a similar order of acquisition of monolingual and bilingual children of direct and indirect object relationships. In the area of subject-verb agreement, comprehension, but not performance, was undifferentiated in both monolingual and bilingual children. (JB)