阅读下面短文，从每题所给的四个选项中，选出最佳答案。
Hi, dear boys and girls! Do you know how to be a healthy kid? Here are some rules you should follow.
First, eat different foods, especially fruit and vegetables. You may have a favorite food, but you'd better eat something different, if you eat different foods, you will probably get more nutrients (营养物质) your body needs.
Then, drink water and milk as often as possible. When you're really thirsty, cold water is the No. l choice. Milk is a great drink that can give you more calcium (钙) your body needs to grow strong bones .
Next, listen to your body. How do you feel when you are full? When you are eating, notice how your body feels and when your stomach feels comfortably full. Eating too much will not make you feel comfortable and make you fat.
Afterwards, limit (限制) screen time. Screen time is the time you watch TV, DVDs and videos, or using computers. It is good to take more exercise such as basketball, bike riding and swimming. You can't watch TV for more than two hours a day.
Finally, be active. One thing you'd like to do as a kid is to find out which activity you like best. Find ways to be active every day.
Follow these rules and you can be a healthy kid.
【小题1】You have to eat different kinds of foods especially _________.