Is this her Dress?
Yes, it is.
Is this his T-shirt?
Yes, it is.
Is this his Bag?
Yes, it is.
Is this HER hat?
No, it isn't. This is HIS hat.
Is this her Hat?
Yes, it is.
Is this HIS bag?
No, it isn't. This is HER bag.
Is this HER t-shirt?
No, it isn't. This is HIS t-shirt.
Is this HIS dress?
No, it isn't. This is HER dress.