2019年12月英语六级考试阅读提升4

同学们可能在刷题数量达到一定程度后会遇到瓶颈，正确率始终上不去，这就需要大家换一个思维去思考，比如重新回到基础练习，不看正确选项，先通读全文，看自己是否能够理解文章含义，再慢慢提升自己。今天坦途网英语六级考试频道就带来阅读提升练习，大家可以查漏补缺。

Salt and Metabolism

Just how salt became so crucial to our metabolism is a mystery; one appealing theory traces our dependence on it to the chemist ry of the late Cambrian seas. It was there, a half billion years ago, that tiny metazoan organisms first evolved systems for sequestering and circulating fluids. The water of the early oceans might thus have become the chemical prototype for the fluids of all animal life - the medium in which cellular operations could continue no matter how the external environment changed. This speculation is based on the fact that, even today, the blood serums of radically divergent species are remarkably similar. Lizards, platypuses, sheep, and humans could hardly be more different in anatomy or eating habits, yet the salt content in the fluid surrounding their blood cells is virtually identical. As early marine specics made their way to fresh water and eventually to dry land, sodium remained a key ingredient of their interior, if not their exterior, milieu. The most successful mammalian species would have been those that developed efficient hormonal systems for maintaining the needed sodium concentrations. The human body, for example, uses the hormones renin, angiotensin, and aldosterone to retain or release tissue fluids and blood plasma. The result, under favorable conditions, is a dynamic equilibrium in which neither fluid volume nor sodium concentration fluctuates too dramatically. But if the body is deprived of salt, the effects soon become dangerous, despite compensatory mechanisms.

英语六级考试是可以刷分的，所以上半年成绩不理想的同学可以继续复习，现在时间还很充裕，大家都是有学习基础的，可以通过本文提升训练，查阅资料弄懂本文主旨，好记性不如烂笔头，遇到不懂的单词要记下来，没有把握的地方一定要做好笔记，以后复习再巩固一遍，相信大家都会成功的。