Final answer:
The patient clearly understood the education about measures to prevent venous thromboembolism.
Step-by-step explanation:
The statement that indicates the patient clearly understood the education about measures to prevent venous thromboembolism is: 'I'll keep pillows under my knees to help my blood circulate better.' This statement shows that the patient knows the importance of elevating the legs to improve blood circulation and prevent blood clot formation. Elevating the legs reduces the risk of blood pooling in the deep veins of the legs, which can lead to the formation of a blood clot. It is an effective measure to prevent venous thromboembolism.