例子：lipid is non-polar hydrocarbon (成分） so i have to ask myself, what properties hydrocarbon got? Oh ya, hydrocarbon has many energy-riched hydrocarbon bonds (property) So, what can these bonds do? These hydrocarbon bonds can be broken to produce energy ( function ) So what are the examples? Eg Stored Fats are burned when there is low glucose sourse. The fats act as energy storage .
当然 这样读书的好处不仅如此 例如如果我读了 lipid 然后现在读glucose 我看到，eh? Glucose also has hydrocarbon bonds? So this means Hydocarbon can produce energy? Hence glucose can also serves as energy source? How come both glucose and lipids can produce energy? What is the difference? Where is the difference? 然后，相反地，读proteins 时 看了他的成分 没有很多的hydrocarbon bonds 所以呢？它就不是 energy source了。