His mother acknowledged that it was obvious he did not really understand what he had just read. Not at all. Rather, they must be used with their limitations in mind. Workbooks are not teachers and are rarely an indicator of a student's ability to understand or to think beyond the literal level. Practice of any objective can take a variety of forms.
Workbooks are only one of many choices.
Other follow-up activities include compositions, games, projects, and presentations. There are times the teacher does not require a deeper level of comprehension of material. As a casual introduction to taking standardized tests. These types of tests supply questions and choices. That format is something with which students need to become familiar.