How many years ago does this story happen?

故事发生在多少年前？

Who did live among the trees?

还有谁住在树林里呢？

节选原文：

Little House in the Big Woods - by Laura Ingalls Wilder

(Word Count: 275)

 Once upon a time, sixty years ago, a little girl lived in the Big Woods of Wisconsin, in a little gray house made of logs.

 The great, dark trees of the Big Woods stood all around the house, and beyond them were other trees and beyond them were more trees. As far as a man could go to the north in a day, or a week, or a whole month, there was nothing but woods. There were no houses. There were no roads. There were no people. There were only trees and wild animals who had their homes among them.

Wolves lived in the Big Woods, and bears and huge wild cats. Muskrats and mink and otter lived by the streams. Foxes had dens in the hills and deer roamed everywhere.

To the east of the little log house, and to the west, there were miles upon miles of trees, and only a few little log houses scattered far apart in the edge of the Big Woods.

So far as the little girl could see, there was only the one little house where she lived with her father and mother, her sister Mary and baby sister Carrie. A wagon track ran before the house, turning and twisting out of sight in the woods where the wild animals lived, but the little girl did not know where it went, nor what might be at the end of it.

The little girl was named Laura and she called her father, Pa, and her mother, Ma. In those days and in that place, children did not say Father and Mother, nor Mamma and Papa, as they do now.