Match the words from the left column with their definitions on the right:

A very simple process from the modern perspective, these developments took about 400 000 years.

With both stones and bones as materials, and with some knowledge of how to afix handles, the rate of invention of new tools began to speed up.

Over the past few centuries the rate has speeded up to the point where rapid change is normal and expected.

It still is difficult to appreciate the lenght of the period during which it (culture) has grown and how much of what we customary think of as culture today has appeared in the very recent past.

All of modern technology has developed in less than 1/2500th of the total time it has taken for human culture to reach its present level of development. (См. Part II, “A Grammar Workbook” p. 175. Инфинитивный оборот, вводимый предлогом for (“for-phrase”)).

In order for diffusion to operate on a substantial scale, there must be separate societies that have existed long enough to have elaborated distinctive ways of life.

One dramatic way of representing the growth of culture over time is to select an arbitrary starting date.

The explanation for this situation is to be found in the fact that culture grows in two ways.

If communal living and equal sharing on any scale are to become part of the American way of life, it will represent a radical break with the past and will require re-organization of much of the remainder of American life. This is not to say that it will not happen.