To put the sentence in its negative form, we must state that Shekhar was not in the habit of playing with marble. The sentence will then be written as: Shekhar was not used to playing with marble in his childhood days.
A sentence in the negative form must show the reader that something has not been accomplished, has not been completed, or does not exist. In this case, it is important to recognize the verb in the sentence and show how the action of that verb was not performed.
The verb is the word that shows action. In the case of the sentence above, the verbs are the words "used" and "to play."
More information about verbs is at the link:
https://brainly.com/question/13956220