Преобразуйте слова (в скобках), так, чтобы они грамматически соответствовали содержанию текста.
1. Dogs (to become) popular in ancient Greece, Rome and Egypt
2. People (to know) that dogs could be used to work in (much) spheres of life.
3. But probably the (important) think about them is their devotion.
4. Most of (they) are really friendly.