根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Food is very important. Everyone needs to  1 well if he or she wants to have a strong body. Our 2 also need a kind of food. This kind of food is 3. We begin to get knowledge even when we are very young. Small children are 4 in everything around them. They 5 something while they are watching and listening. When they are getting older, they begin to 6 story books, science books ... anything they like. When they find something new, they love to ask questions and 7 to find out answers. What is the best 8 to get knowledge? If we learn by ourselves, we will get the most knowledge. If we are 9 getting answers from others and do not ask why, we will never learn well. When we study in the 10 way, we will learn more and understand better.