Question

I gave him the grammar book.( change into passive voice)​

Answer 1

$\huge\sf\underline{Required\:Answer}$

He was given the grammar book by me.

Explanation ↴

The passive voice of the verb with two objects is formed by changing either of the two objects (preferably the Personal Object) into the subject and retaining the other as the 'retained object'.

Answer 2

${\large{\underline{\underline{\textbf{Required Answer :}}}}}$

$\text{Given :}$I gave him the book.

$\text{Passive voice :}$ He was given the grammar book by me.

${\large{\underline{\underline{\textbf{Explanation :}}}}}$

$\text{subject(I) + verb(gave)+Indirect object(him)+}\\ \text{direct object (The grammar book)}$

$\textbf{changes to:}$

$\text{New subject (He) + verb (was given) + direct object}\\\text{(The grammar book ) + by + new object (me)}$

$\bigstar$The given sentence is in the active voice, as the subject I performs an action gave against the object the grammar book.

$\bigstar$If this sentence is changed to passive voice, then the subject is also changed, in order to retain the meaning of the sentence.

$\bigstar$So, the object takes the place of the subject and vice versa and the word by is introduced as now the subject receives the action by the object.

$\bigstar$The verb form of the sentence is also changed from active form to passive.