please give me the pictures of grasslands and forest of different parts of world provided with the description about them ?

For grasslands, start with
http://www.blueplanetbiomes.org/grasslands.htm
From there, click to web sites for the North American prairie, South American pampas, and the steppes of Asia and Ukraine. Those are the main three grassland areas of the world.

For forests, start with http://www.worldbiomes.com/biomes_forest.htm and explore the various links from there. There are several different types of forest.