示例：
Spring is in March, April and May.
In spring, it's warm. We fly kites and go boating.
Summer is in June, July and August.
In summer, it's hot. We eat ice cream and go swimming.
Autumn is in September, October and November.
In autumn, it's cool. We climb mountains and have picnics.
Winter is in December, January and February.
In winter, it's cold. We go skating and make snowmen.
