Every sentence has two parts: the naming part and the action part.
The naming part tells who or what the sentence is about. It is called the subject.
The kitten is sleeping peacefully.
The girls are having tea together.
Jamie plays the trumpet well.
The action part tells something about the naming part. The action part is called the predicate.
The children are running through the field
The elephant is spraying water with its trunk
The trees are swaying in the wind