1. The following text is incomplete. To improve it, and make the meaning clear, add the additional information given below, in the form of Relative Clauses (formal style). Britain before the Romans
About the year 5000 BC, the waters the English Channel and North Sea joined together, and Britain became an island.
The human population of the new island at that time was a few hundreds (1)
.
But at the very time (2)
. A revolution was occurring thousands of miles away in the Near East (3)
. He was learning not merely to hunt and kill for his food, but to keep the animals. He was learning, too, to gather the seeds of the grasses and scatter them about him to grow into the food (4)
. He was learning, in short, to be a farmer.
Men with this new knowledge did not cross the still widening waters between Europe and Britain until about 2300 BC. And when they came they had to keep to the chalky and sandy soils where they could turn the ground over for their seeds to grow. So the area (5)
was very limited.
These first settlers on the chalk ridges were men (6)
. They crossed it only if they had to and they crossed it where it was narrowest. But there were others (7)
men
Living along the coasts of Spain or Britany. When they crossed, it was where the English Channel was wider. The settlements of these people can be distinguished today by their remarkable burial places (8) .
It was about the year 900 BC that a large westward movement of races on the European continent produced another invasion of Britain, by a people (9)
. These were the Celts, and they

Spoke a language (10) .
(from A History of England by J. Thorn, R. Lockyer and D. Smith)
The additional information:
They lived by hunting with roughly made stone instrument.
This separation of Britain from the continent was taking place.
It was to change for ever the life of man.
The animals provided food in captivity (неволя).
He wanted to make food.
They settled on this area.
To them the sea was a natural barrier.
For them the sea had fewer terrors.
Its roof is a great stone.
These people are the first to have left on this island something more than material remains.
The tongues of Ireland, Wales and the highland of Scotland are direct descendants of this language.