This is a Problem-Solution Paragraph

The Invisible Danger

Nowadays strong EMF (Electro-magnetic Field) radiation is considered as pollution. The strong radiation threatens human health. The principle behind this is simple. Our body is made of molecules which are sensitive to EMF. When EMF radiation pass through human, molecules inside the body will receive thermal energy. If the radiation is strong enough, molecules will be heat up. For example, if a person put his hands on large transmitting antenna, the hands will be burned. That’s one of the most important reasons that large antenna must be built far away from living area.

In China, now a specific kind of EMF radiation which has become the main polluting source is cell phone radiation. It affects human health, because cell phone will be usually put close to human brain when it is used. The cell phone radiation has a direct impact in the brain. Now in China, the business circle of cell phone is very short. A new model of cell phone can mostly last one year in the market. And the safety standard of EMF radiation is not strictly controlled. As a result, cell phone radiation has become an invisible danger in China.

Solving this problem is not a one side job. Firstly, government must set strictly laws to regulate those cell phone producers. Secondly, lower power cell phone technologies should be used to reduce the EMF radiation strength. Thirdly, we need to use cell phone less in our daily life.

This is a Cause-Effect Paragraph

Nowadays strong EMF (Electro-magnetic Field) radiation is considered as pollution. The strong radiation threatens human health. The principle behind this is simple. Our body is made of molecules which are sensitive to EMF. When EMF radiation pass through human, molecules inside the body will receive thermal energy. If the radiation is strong enough, molecules will be heat up. For example, if a person put his hands on large transmitting antenna, the hands will be burned. That’s one of the most important reasons that large antenna must be built far away from living area.

In China, now a specific kind of EMF radiation which has become the main polluting source is cell phone radiation. It affects human health, because cell phone will be usually put close to human brain when it is used. The cell phone radiation has a direct impact in the brain. Now in China, the business circle of cell phone is very short. A new model of cell phone can mostly last one year in the market. And the safety standard of EMF radiation is not strictly controlled. As a result, cell phone radiation has become an invisible danger in China.

This is a comparison and contrast paragraph.

As the development of modern technologies, more and more semi-conductor based high tech products are being used in our daily life. Usually, the semi-conductor industry was called “Clean Industry”, because the products must be made in a professional clean house. However, most of these products are thrown after their life circle. Toxins in these trashes are normally lead, mercury, chromium, arsenide, and indium. As chemistry research showed, these elements are considered to be unhealthy for human. A Certain amount of these elements will cause serious diseases. This is the dark secret of the “Clean Industry”.

However, those metal elements will be great potential resource, if they can be recycle properly. Developing courtiers and developed countries made different approaches. In the Pearl River Delta of Southern China, cheap labors from country side are paid to open and sort the parts of different products like TVs, monitors, and keyboards. They burn cables to get copper. Air is polluted by burning plastic shield of the cables. They put the circuit boards and chips in acid to get gold. Then they will dump the acid into a nearby river. Soil and water are polluted by metal toxins. While in a country like Japan, they have better ways to recycle the trash. All these trash will be sent to some special factories. At those places, the trash will be taken care of specialized workers. They will use mechanical tools and chemical acid to get useful metal by following strict procedure. For example, the used Acid are not allow to be damped into rivers directly.