This paper explores the syntactic and semantic character of previously undescribed sentence complements (SCs) in Emai, a Benue-Congo language of Nigeria's Edoid group. Data come from ongoing documentation incorporating oral narrative texts as well as dictionary and grammar descriptions. To delineate the grammatical properties of SCs, the paper examines Emai's tense-aspect-modality (TAM) particles. They consist of tense/aspect inflection through tone and particle marking, auxiliary particles from the modality classes deontic and epistemic, from the relative tense class and from predicate negation. Although influential linguistic investigations have emphasized the constraining role of matrix clause verb on sentence complements, the findings suggest that SCs themselves may constrain their grammatical properties and that their modal character may prove fruitful for grammatical investigation. (Contains 13 references.) (SM)