what do u mean by object of the sentence?
An object of a sentence is a part of the predicate of the sentence. It tells us the person or thing upon whom or which the subject is acting upon. In short, it tells us the person or thing upon which the verb is being performed.
For example:
Natalia sang a song.
('Song' is an object in the sentence because the subject 'Natalia' performs the verb ('sang') upon the object 'song'.)
Look at a few more examples:
I bought a book.
Taj Mahal is in Agra.
The bag is on the table.