Many parts of the world have four seasons. They are spring, summer, fall and winter. Spring follows winter. It becomes warmer and the days become longer. Plants begin to grow and many animals have babies. Summer is the hottest season. It does not get dark until late. Plants grow fast. In fall the days get shorter. The weather turns cooler. Trees may lose their leaves. Some birds fly to warmer places. Winter is the coldest season. It gets early in the evening. Plants stop growing and many trees are bare(光秃) 。