填空题

Miracle of the Forest
When you walk into a National Forest, you really believe you are the first person who has ever been here. Funny thing is, you are not.
These forests have been used for over a hundred years. From this timber stand, settlers used wood to build their homes. And ties were cut for the railroad. Hard to believe, isn’ t it
But that’ s the Miracle of the Forest. With careful management these forests have re newed themselves, year after year, providing us with all kinds of benefits. And that’ s why we call them "Forever Forests".
Come to see for yourself! And get involved with the new "Forests For Us" program and tell people all about the Miracle of the Forest.
For more information write: Forest for US, P. O, Box 2000, Washington, DC 20013.
Miracle of the Forest
Duration that has been used: (46) .
Usage of the forest:1. (47) .for the building of houses
2. (48) for the railroad
The reason that we call them" Forever Forests":
1. (49) themselves with careful management
2. providing us with lots of (50) year after year