Відповіді: Стр.146 (1)

1. Carelessness is often the cause of fires.

2. The cause of the accident is still not known.

3. What is the cause of lightning?

4. Scientists attribute changes in the weather to natural reason.

5. The cause of earthquakes is the heat inside the earth.

6. Never stay away from school without good reason.

7. There is no reason to suppose he will forget.

8. What was the reason for your refusal to go there?