Food is colorful. Some food is green, some food is red, and some is black. Now more and more people like to have black food--black rice, black beans, black grapes. Why do they like black food? * Black food can make grey hair into black hair. * Black food is good for the heart.  * Black food can help children become smart. * Black food can also help women look young. Black food is very good, but we need food with different colors. Doctors say that it isn't good to be _ about food. So we had better eat all kinds of food. A seven-year-old boy often has black food, so he can become   _  .
smart young old tall