Purpose: This study tested the feasibility of a method designed to assess children's sensitivity to tense/agreement information in fronted auxiliaries during online comprehension of questions (e.g., "Are the nice little dogs running?"). We expected that a group of children who were proficient in auxiliary use would show this sensitivity, indicating an awareness of the relation between the subject-verb sequence (e.g., "dogs running") and preceding information (e.g., "are"). Failure to grasp this relation is proposed to play a role in the protracted inconsistency in auxiliary use in children with specific language impairment (SLI). Method: Fifteen 3-year-old typically developing children who demonstrated proficiency in auxiliary use viewed pairs of pictures showing a single agent and multiple agents while hearing questions with or without an agreeing fronted auxiliary. Proportion looking to the target was measured. Results: Children showed anticipatory looking on the basis of the number information contained in the auxiliary ("is" or "are"). Conclusions: The children tested in this study represent a group that frequently serves as a comparison for older children with SLI. Because the method successfully demonstrated their sensitivity to tense/agreement information in questions, future research that involves direct comparisons of these 2 groups is warranted.