New inventions come to us every day, just as something new happens to us each day. You cannot believe one hundred years ago there would be computer; you cannot imagine fifty years ago we have flash drive nowadays, either. The whole world is having a stunning change every minute; you do not even know what will emerge on tomorrow morning. What do you think is the most useful invention in the world?

According to the benefits the inventions bring, I think the greatest inventions are electronic cigarettes and flashlights. First of all, let’s see what electronic cigarette is.

Electronic cigarette is the cigarette without tobacco, harmful chemicals, and tar, which emulates the physiological and psychological process of smoking. The cigarettes are rechargeable and use advanced micro-electronic technology to deliver nicotine to the user. The nicotine cartridges come in a variety of concentrations making it easy for you to slowly breakdown your intake. The draw from a cigarette is almost identical to traditional smoking. The ‘smoke’ which is produced is actually vapor and therefore a friendlier alternative to your environment. Electronic cigarettes are in different strengths so that you can continue to SMOKE in your usual and familiar fashion but in a less harmful manner. Several flavors are available for you to choose from mint, strawberry, and chocolate. Some brand of electronic cigarettes also provides refills. Some electronic cigarette users say this cigarette does not give them smelly breath or yellow fingers. Last but not the least, these electronic cigarette smokers are not refused to smoke electronic cigarettes in office or at home. The electronic cigarettes determine your intake of nicotine, which is also ideal to slowly reduce your smoking habit. As a result of no second-hand smoke, no yellow teeth or fingers, they are popular among businessmen. What’s more, electronic cigarette is much cheaper than traditional cigarette.

Well, I will explain why I think flashlight is one the greatest invention. In ancient times, people use torch to explore, drive beasts away or work at night especially outdoors. However, whether the torch works well depends on the torch itself and the weather. Obviously, there are too many factors to consider. Thanks to the invention of flashlight, our life has a great change. There are several types of led flashlights in the market nowadays.

1. LEDs: Short for light-emitting diodes, a simple type of semiconductor. They excel in energy efficiency while offering good, all-purpose proximity lighting for camp chores, map-reading and close-up work.

2. High-output LEDs: 3-watt LEDs rival the brightness of pressurized-gas bulbs; 1-watt LEDs produce a light intensity that matches up well with standard incandescent--only they use much less battery power.

3. Xenon, halogen or krypton bulbs: Incandescent bulbs that contain a pressurized gas such as xenon. When introduced into a bulb's glass casing, these gases prevent oxidation of the filament, controlling soot buildup that tends to darken traditional bulbs. As a result, these bulbs burn with high intensity.

4. Incandescent bulbs: Traditional bulbs are filled with an inert gas, such as argon; they usually cast farther-reaching beam and produce higher lux numbers than standard LEDs.

The inventions above bring a lot of convenience to our life. What do you think is the greatest invention?