Ex. З, p. 15


1. Sounds were made by pre-human creatures.

2.   Communication was made more complex.

3.   First words were written millions of years ago.

4.   Some changes were explained by scientists.

5.   Words were added to a vocabulary.

6.   Words were brought from one language to another.

7.   A standard form of a language is used on radio and television.

8.   A language is called dead when nobody speaks it.