（1）We found that only fifteen percent of our students exercise every day．Forty﹣five percent exercise four to six times a week． Twenty percent exercise only one to three times a week． And twenty percent do not exercise at all!

　　（2）If you go without sleep， you might have problems with your memory or with your concentration（注意力）．In order to concentrate at school or perform well in tests， we really need to get a good night's sleep．

　　（3）Dr． Green says all these activities can cause a lot of stress for children． "Kids should have time to relax and think for themselves， too． Although it's normal to want successful children， it's even more important to have happy children．

　　（4）Yes， you knew I was going to say this! It is so important． Smoking is not cool． It is dangerous． It harms nearly every part of your body． Think about how your family and friends will feel， and think about what it will do to your health．

　　（5）I have never been very active， and I do not like sports． I have always wanted a pet， so my parents gave me a dog for my birthday． Now I get exercise by taking him for a walk every day． Now I feel really healthy．

Choose the best topic from A to F according to the meaning of the passage．

A． Not getting enough sleep has effects on our brain's work． B． Have a healthy diet!． C． Say no to smoking! D． Our survey about doing exercise． E． Taking my pet for a walk makes me healthy． F． Too much pressure is not good for a child's development．