I was invited to be a lecturer to give a presentation.
The topic of the presentation is kind of energy
     saving technology.
Many factories release many pollutants (including
   chloride compounds, sulfide compounds,
   and carbon dioxide gas into atmosphere.
The animals release methane, carbon dioxide
    gases into atmosphere.

The chloride compounds in the atmosphere
    destroyed the ozone layer.
The ozone layer helps to protect the people from
     the sun's harmful ray (i.e. ultraviolet ray).
The sulfide compounds in the atmosphere caused
    the acidic rain.
The carbon dioxide in the atmosphere caused the
    green house effect.

The lecture location was at Prince Hotel.
The buffet served by the Hotel was so delicious.
After finishing six hour lecture, I strolled down the stairs

    and look in the store windows.

The hotel has a lot of boutiques that sell some nice articles.

While I was meandering at the Hotel, I stretch my body.
Stretching made my muscles more flexible and
      increased blood circulation.