100年后：
When time comes to 2109,what the world will be like?Now,let me show you around the cities and countrysides.
Due to the heavy pollution during the 21st century,the sky always show us the grey face instead of blue as 100 years ago.Less and less brids can be seen in the city and the little chilren even don't know what the brids looks like.
As to the countryside,the solution is not better.The increasingly number of factory had been founded ,which makes the river so durty that no fish can live in.
And what the things will be in the further furture?We have every reason to believe we will have some measures to solve this international problem ,and by this,our world would become better and better .