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1-dropping

2-to be

3-open

4-open

5- opening, closing

6-carry

7-to come

8-to tell

9- dancing

10-feel

11-to smoke

12-to tell

1) Studying abroad seems difficult but interesting to many students.

    CHALLENGING

    Students understand how challenging it is.(to study abroad)

2) Studying abroad  is similar to studying at one's  home college.

    DIFFERENT

    Studying abroad is not different from studying at home.

3) When you are abroad you can miss your relatives very much/

     DEPRESSED

    While abroad you feel (are) depressed because you can't see parents and  relatives.

4) You are in charge of all your things.

    RESPONSIBLE

   You are responsible for everything.

5) You can learn a lot about yourself and the world while studying abroad.

   BEST

  Studying abroad is the best experience you can have

Environment - a set of components of the environment, natural and man-made natural objects and man-made objects.
Components of the environment - land, minerals, soils, surface and ground water, air, flora, fauna and other organisms, as well as the ozone layer of the atmosphere and near-Earth space, providing a set of favorable conditions for the existence of life on Earth.
Pollution - into the environment of matter and (or) energy, property, location or number of which have a negative impact on the environment.
Contaminant - a substance or mixture of substances, the number and (or) concentrations exceed established for chemical substances, including radioactive and other substances and microorganisms standards and have a negative impact on the environment.
Air pollution - a really serious problem. Air is composed of oxygen, nitrogen, water vapor, and, thanks to our civilization, of a variety of toxic particles. The more of these particles in the air is, the less room is left in the atmosphere for oxygen.
   The problem of air pollution is not limited to the space outside. The air inside our homes and offices can be as dangerous to your health. The main source of pollution - cigarette smoke, but it is not the only one. Toxins are allocated even when you just cook. Every time you scratch the Teflon non-stick coating is allocated enough toxins to kill a canary.
 Greenhouse effect, which we all have been associated with the phenomenon of global warming, caused by toxic gases. The main enemy of clear atmosphere - methane. It is released from the decomposition of sewage.
Greatly affects our waterways. In every neighborhood, in every city there drain sewer, storm water from the highways and municipal enterprises directly into the river. Everything goes into the water, passing minor cleaning steps.