What are two quotations from Katherine Mansfield's "The Doll's House" that show the Kelveys are different from other families?

The Kelvey girls are from the lower class, whereas the other girls in the story are from families of a higher social status.
It is important to note the setting of this short story is a small village in New Zealand in the early twentieth century. At this time, New Zealand was still a colony of Great Britain, which had a rigid class system. Therefore, those who moved to New Zealand brought this class system and its accompanying attitudes with them.
The Burnells are people of wealth and privilege, a class that in England would not associate with the lower class. Because there is only one school, however, all children attend classes together, regardless of socioeconomic status.

But the line had to be drawn somewhere. It was drawn at the Kelveys. Many of the children, including the Burnells, were not allowed even to speak to them... The Kelveys were shunned by everybody.
Even the teacher had a special voice for them, and a special smile for the other children when Lil Kelvey came up to her desk with a bunch of dreadfully common flowers.

The Kelvey girls wear clothes made from bits of material donated to Mrs. Kelvey, who works as a washwoman,

who went about from house to house by the day. This was awful enough. But where was Mr. Kelvey? Nobody knew for certain. But, everybody said he was in prison.

When the other girls are allowed to see the charming doll's house, Lil and our Else "hovered at the edge" and listened. As Isabel Burnell conducts the tour for the girls, she points out the carpet and the bed and its little covers. Isabel's sister Kezia points out the little amber lamp, saying, "The lamps best of all." Afterwards, the other girls put their arms around Isabel and leave. 

Only the little Kelveys moved away forgotten; there was nothing more for them to hear.

When Kezia asks her mother if she can invite the Kelveys, she is told, "Certainly not!" Soon, then, all the girls but the Kelveys have seen the doll's house.