The simple subject is the main noun or pronoun that tells what the sentence is about.

1- The batter swung at the third ball. (main noun as simple subject)

2- She hit a high pop foul. (main pronoun as simple subject)

A simple predicate is the verb or verb phrase that expresses action or being about the subject.

1- The crowd cheered after the touchdown. (main verb as simple predicate)

2- The team will practice on Saturday. (main verb phrase as simple predicate)

A complement completes the meaning of a verb. It may be one word or a group of words. One kind of complement is the direct object. A direct object answers the question what? or whom? after an action verb: Mario picked some flowers for the mantel. (Mario picked what?)

A direct object may have more than one part.

The farmer carried the calf and the lamb through the floodwaters.

Another kind of complement, the indirect object, answers these questions following an action verb: to whom? for whom? to what?

The child threw her father and mother a kiss. (The child threw a kiss to whom?)

The crowd gave our team a cheer. (The crowd gave a cheer to what?)