在托福的备考过程中，对于阅读来说，单凭一些技巧是很难提升自己的托福阅读能力的，大量的练习还是必不可少的。这将对考生们打开思路、解答题目很有帮助，下面我们就为大家提供了The roots of jazz的阅读材料，希望能为大家的托福备考带来帮助。
Never a happy topic， bed wetting is a very distressing problem for five to seven million American kids. If we can’t explain why some people like to pick on these kids， can we at least shed some light on what causes bed wetting?
At one time， people punished bed-wetters for acting badly， but today scientists believe that this condition has several physical causes. Some kids suffer from problems like infections or anatomical defects that can be easily identified and treated.
Other causes are harder to pin down. One promising area of research is on the kidney hormone ADH. We all produce more ADH hormone at night. ADH signals the kidney to slow down production. This is why we don’t go to the bathroom for eight hours at night but could never last that long between bathroom breaks during the day. Some children who wet their beds do not produce enough ADH at night. When given drugs that boost this hormone， they stop bed wetting.
Finally， some kids simply have small bladders and an undeveloped nervous system. The good news is that these kids， like most bedwetters， will grow out of it as their bodies develop and mature.
