I'm not a native English speaker.  
We were supposed to use the verb *be* instead of the verb *belong* using possessive pronouns. 

The question is 

 - *Do those toys belong to her?* 

The answer given by some is 

 - *Do those toys are hers?*

Isn't it simpler to say: 

- *Are those toys hers?*

Sorry for bringing a confusing issue and not stating it properly.  
Thanks a lot. I appreciate your concern very much. I enjoy learning English.