As we all know, every coin has two sides. Every thing has a 'However'.

Science makes our life more easier. Thousands years ago, we cannot go to the place where is far away from our city. If we want to do that, we need to get a hurse and spend several days some time even a week to get to another city. Now, we just need few hours to travel to another city.

You may say that there is nothing bad. We have more time and more comfortable. But we forgot something while we are sitting on the plane or on a train. We forgot to watch outside the window where also have so many beautiful sights to see.

Also, cars and trains make more pollution into the air. city's air are dirty because there are so many factory and cars. On the other hand, country's air are fleash and clean since there are few factory and many people do not use car.

So we see, science is two-edged. Many other things are just like science, such as fast food, nuclear energy, cellphone and so on. They do have convenience but they also have many problems.

Finally, I just want to say that everything has a 'However'. Do not just think on one side and forget the other side of it. There is always a 'However'

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