A、The southeast. B、The northwest. C、The northeast. D、The south. A原文中提到，美国的东南部被称作Kidney Stone Belt，在那里男性患肾结石的几率是美国东北部和西北部男性患病率的2倍

If you were asked to list the consequences of climate change and increasing global temperatures, this may be one of them—kidney stones. The study just published shows more and more people will suffer from the disease while it’s getting warmer and warmer. Kidney stones and hard crystalline masses develop inside the body from the minerals in urine, and they can be incredibly painful.
    Well, in the United States in particular, there is a regional variation in kidney stones. In the southeastern US, called the Kidney Stone Belt, the risk for males of kidney stone formation is double that in the northeast or the northwest. And several reports have shown that this difference in the regional distribution, approximately 70％ of which, can be explained by annual temperature difference. So it proves again the kidney stones, the upper track stones, can be affected by temperature.
    And how can that link work? How can temperature, you know, whatever it is, a sunny day outdoors, a cold day outdoors, how can you link them to a human developing kidney stones? Clearly urine volume correlates inversely with temperature. So the warmer the temperature, the lower the urine volume and then therefore the more concentrated the urine is.
    The human body lets out about the same amount of salt every day but the more water you drink then the excess water comes out and dilutes the urine. So if you don’t drink enough water or if you perspire a lot or lose water by other ways, then your urine becomes more concentrated and that’s very much.
    According to the recent released climate models from IPCC, which many people may be familiar with, it seems at least 90％ certain the global warming has occurred and will continue and probably accelerate. Then it’s certain that kidney stones are more common in warmer regions. So the remaining question is whether there would be a significant rise in cases and cost, and our study shows that something like 2 million more new cases strictly attribute to climate by 2050, probably 25％ or 30％ increase in the cost of treatment of those kinds of illnesses by 2050 again. And then the distribution of those increases will be non-uniform, so some areas will see 30％, perhaps even 50％ increase.
    Questions 16 to 18 are based on the recording you have just heard.
    16. Which part is called the "Kidney Stone Belt" in the US?
    17. What will happen if you lose too much water?
    18. What will happen by 2050 according to the study?