Question

1. The dog is playing with (she, her). she her* 2. The librarian asked my sister and (he, him) if they would talk more quietly. he him*

Answer 1

1. The dog is playing with her.

You need to use the pronoun her because it is the object of this sentence. The pronoun she can only be used as the subject of a particular sentence, and in this one, we can see that the subject is the dog, therefore, it cannot be her. So instead, you should use the object pronoun, which is her.

2. The librarian asked my sister and him if they would talk more quietly.

The explanation for this example is the same - since the boy is the object of the sentence (along with my sister), you need to use the objective pronoun, which is him. The pronoun he is used as a subject of a sentence, and we can see that the subject here is the librarian, so it cannot be the boy.

Answer 2

1. Her - used as the object of a verb or preposition to mention to a female individual before stated or effortlessly recognized.
2. Him - used as the object of a verb or preposition to mention to a male individual or beforehand stated or simply recognized.