3.
1 In winter, there is a lot of snow in the mountains .
2 There is a lot of fish in the river. People go there to catch the fish.
3 There is more water in the lake after heavy rain. People go there to swim.
4 There are a lot of trees in the forest and the air is very clean.
5 There is a lot of sand in the desert. Sometimes people go there to ride camel.
6 There are no trees in the steppe, but there is grass. People go there to see interesting plants and animals.