Height is just one of the thousands of features that your genes(基因) decide. In fact, because you have two parents, your genes provide you a height that usually lands somewhere between the height of each parent. If both your parents are tall, then most probably you will be tall, too. But if you have questions about how tall you're going to be, ask your doctor if he or she can help you find it out.

    But genes don't decide everything. For example, eating an unhealthy diet can keep you from growing to your full potential(潜力). Getting plenty of sleep and enough exercise will help you grow to the expected height.

    No doubt you're wondering how fast you should grow. There's no perfect or right answer. Generally speaking, kids grow about two inches(six centimeters) a year between age 3 and the time when they start puberty(青春期).

    Your doctor will know how your growth has been going over the years, how you've been growing up to this point, and what other changes your body may be going through.

    Don't be scared if you seem to have grown a lot in a very short time. Everyone has a growth spurt(高峰) during puberty. The age for starting puberty is about 10 for girls and about 11 for boys. But it can be earlier or later-between 7 and 13 for girls and between 9 and 15 for boys.

    You'll usually begin to notice that you're growing faster about a year or so after your body starts to show the first changes of puberty.

    Up to two thirds of children don't get as much sleep as they should do, and this can make them nervous and slower at school, researchers say.

    So 1 should young people sleep each night? The answer is between 8 and 10 hours.

    If you don't get enough sleep at night, you'll have 2 energy the next day. But the researchers say many children have missed out on 4, 500 hours of sleep 3 the time they are 7 years old. They say that children miss sleep because they have TVs and computers in their rooms and 4 parents don't read to their younger children at night any more. The traditional "bedtime story" helps children to relax and fall asleep 5 . Children with TVs and computers in their bedrooms are more likely to sleep badly, and to get less than 8 hours' sleep. Even losing one hour's sleep a night can mean that children do worse at school.

    German scientists think that your 6 keeps working while you are asleep. To show that they were 7 , they gave two groups of people a problem to work out. One group went to sleep and the other group stayed 8. The result? The people who slept worked out the answer more quickly, suggesting that their brains had been trying to 9 the answer while the people were asleep. So, make sure you get enough sleep tonight, 10 you'll be at your best tomorrow.

参考词汇：keep healthy, train a person's character, on foot, P. E. classes, climb mountains

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Let's Do Exercise Together

    It's very important for us to do exercise……

—He lost his bike.