【英语时差8，16】肾结石

 Kidneys are extremely useful organs. Located below the ribs¹ toward the middle of the back, kidneys make urine by filtering excess water and waste from the blood.  Scientists have not yet determined² why or how it happens, but on occasion crystals separate from the urine and build up on the inner walls of the kidneys, forming dreaded³ kidney stones composed largely of calcium⁴ and a mixture of other substances. Urine has chemicals that inhibit⁵ crystal formation, but for some people these chemicals don't work properly, and stones form.

"Stone" is actually a misleading word, since we might tend to think of a round, smooth pebble⁶. Although some kidney stones are round and smooth, others are jagged, shaped like tiny starfish. If the stone is roughly the size of a grain of sand and can therefore travel easily through the urinary tract⁷, it may pass unnoticed. But when a lima-bean-sized-stone becomes lodged⁸ in the urinary tract--a tube the width of a spaghetti strand--you're in for a world of pain.

When a sizeable stone moves in the urinary tract, pain suddenly erupts in the back and side near the offending kidney. Discomfort⁹ only increases as the muscles in the urinary tract try to squeeze the stone down toward the bladder, often resulting in mind-numbing pain. What's worse, the stone may cause blood to appear in the urine, which is never a good sign.

Relief comes when the stone finally passes. Drinking as much water as possible can help speed the process along, although it won't dull the pain. And although kidney stones are not normally life threatening, in extreme cases surgery may be necessary.

1 ribs   

n.肋骨( rib的名词复数 )；（船或屋顶等的）肋拱；肋骨状的东西；（织物的）凸条花纹

参考例句：

• He suffered cracked ribs and bruising. 他断了肋骨还有挫伤。
• Make a small incision below the ribs. 在肋骨下方切开一个小口。

2 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

3 dreaded   

adj.令人畏惧的；害怕的v.害怕，恐惧，担心( dread的过去式和过去分词)

参考例句：

• The dreaded moment had finally arrived. 可怕的时刻终于来到了。
• He dreaded having to spend Christmas in hospital. 他害怕非得在医院过圣诞节不可。 来自《用法词典》

4 calcium   

n.钙(化学符号Ca)

参考例句：

• We need calcium to make bones.我们需要钙来壮骨。
• Calcium is found most abundantly in milk.奶含钙最丰富。

5 inhibit   

vt.阻止，妨碍，抑制

参考例句：

• Don't let ego and greed inhibit clear thinking and hard work.不要让自我和贪婪妨碍清晰的思维和刻苦的工作。
• They passed a law to inhibit people from parking in the street.他们通过一项法令以阻止人们在街上停车。

6 pebble   

n.卵石，小圆石

参考例句：

• The bird mistook the pebble for egg and tried to hatch it.这只鸟错把卵石当蛋，想去孵它。
• The pebble made a ripple on the surface of the lake.石子在湖面上激起一个涟漪。

7 tract   

n.传单，小册子，大片(土地或森林)

参考例句：

• He owns a large tract of forest.他拥有一大片森林。
• He wrote a tract on this subject.他曾对此写了一篇短文。

8 lodged   

v.存放( lodge的过去式和过去分词 )；暂住；埋入；（权利、权威等）归属

参考例句：

• The certificate will have to be lodged at the registry. 证书必须存放在登记处。 来自《简明英汉词典》
• Our neighbours lodged a complaint against us with the police. 我们的邻居向警方控告我们。 来自《简明英汉词典》

9 discomfort   

n.不舒服，不安，难过，困难，不方便

参考例句：

• One has to bear a little discomfort while travelling.旅行中总要忍受一点不便。
• She turned red with discomfort when the teacher spoke.老师讲话时她不好意思地红着脸。