I have found that Drawing Builds Comprehension and Engagement, and Differentiates the Work for your Class!
This book report allows students to demonstrate their understanding in two ways, by drawing and writing. For first graders, I would model how to do this report before turning the students loose on it; older children would be expected to be more independent. This report would be an appropriate exercise to check for understanding after a read aloud, and could be used as either classwork or as an assessment.
Retell stories, including key details, and demonstrate understanding of their central message or lesson.