This study aimed to explore students' cognitive patterns based on their knowledge and levels. Participants were seventh graders from a junior high school in China. Three relatively distinct groups were specified by Cluster Analysis: high knowledge and low ability, low knowledge and low ability, and high knowledge and high ability. The group of low knowledge and high ability was not identified. The result not only revealed the discrepancy between learners' knowledge and ability levels, but also provided the evidence on the importance of knowledge as the premise of ability development. The implications to curricular designs and instructional practices were discussed.