Question

Underline the complete subjects and circle the complete predicates:
2. Madan reads a book in the train.​

Answer 1

Subject- madan
Predicate- reads a book
In the train

A subject is what you are talking about in the sentence. Here, we are talking about Madan in the sentence so it becomes the subjects.
Anything apart from the subject is a predicate, so reads a book in the train becomes a predicate.

Hope this helps :3