Evidence from usage-based studies of second language (L2) acquisition reveals that a main source of L2 learners' developing grammars is the L2 input to which learners are regularly exposed. What learners develop from their extended engagement in the sequences of actions comprising the input is not an acontextual system of grammatical units but rather thoroughly social, positionally sensitive grammars linked to the linguistic designs of the sequences. A growing body of research drawing on the theoretical framework and analytic methods of conversation analysis (CA) has identified the recurring interactional activities of L2 classrooms, which, for most adult L2 learners, are a major source of L2 input. Less examined are the linguistic designs of the interactional activities. This is the focus of the study reported here. Drawing on the shared theoretical and methodological framework of CA and interactional linguistics (IL), and building on previous work, the study examines the linguistic designs of information-seeking sequences by which whole-group instruction is accomplished. The focus is on teacher questions seeking factual information, the type of 'knownness' embodied in the questions, and both the actional types and linguistic designs of the student responses they engender. Findings show that while a great deal of opportunities for participation are made available to L2 learners in the information-seeking sequences, the linguistic quality of the sequences is fairly limited in that the questions are designed primarily to engender one word or multiword phrases. These findings suggest that the possible pathways that learners' developing L2 positionally sensitive grammars can take from their extended engagement in these sequences are also limited. For L2 teacher education, studies such as this one can enhance teachers' understanding of the links between classroom input and learners' developing L2 grammars, and the key role the teachers themselves play in designing the linguistic input of their L2 classroom contexts.